[PDF] - Real World Subtraction MP4 Model with mathematics. with PDF Document

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First Grade

Subtraction to 20 Part 1

2015-11-23 www.njctl.org

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Table of Contents Pt. 1

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Subtraction Sentences
Subtraction on a Number Line
Subtraction on a Number Grid
Number Stories
Subtracting Zero
Subtracting 1, 2, 3
Subtracting Ten
Subtracting All
Comparing Groups
Real World Subtraction with Manipulatives

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Table of Contents Pt. 2

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Patterns when Subtracting 10
Fact Families
Fact Triangles
Missing Number Part 2
Missing Number
Get to Ten
Get to Ten Part 2
Lab - Zero Wins
Lab - Math Action Goes Both Ways
Lab - Fact Family Domino Grab

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Standards for Mathematical Practices

MP8 Look for and express regularity in repeated reasoning. MP1 Make sense of problems and persevere in solving them. MP2 Reason abstractly and quantitatively. MP3 Construct viable arguments and critique the reasoning of others. MP4 Model with mathematics. MP5 Use appropriate tools strategically. MP6 Attend to precision. MP7 Look for and make use of structure.

Click on each standard to bring you to an example of how to meet this standard within the unit.

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Real World Subtraction with Manipulatives

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SLIDE 2

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Real World Subtraction with Manipulatives

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Teacher Notes

[This object is a teacher notes pull tab] During this first lesson, the goal is to have students solve real life number stories. By doing this, kids will make real life connections to

subtraction. Before beginning the

actual lesson, have the student act

ut subtraction stories. Ex: Joe

puts three crayons on the table. Two fall off. How many crayons are

n the table? Have them act out at

least 4 stories.

Slide 7 / 188 When we subtract, we break a whole into 2 smaller parts.

7 baseballs in the whole group part part

Slide 7 (Answer) / 188 When we subtract, we break a whole into 2 smaller parts.

7 baseballs in the whole group part part

Teacher Notes

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Demonstrate moving some baseballs into each "part". Discuss how you took the whole and broke it into 2 parts.

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Four turkeys are on the fence. Two fly away. How many turkeys left?

4

Whole

2

(Flew away) Part (Left) Part

How many turkeys are left?

Teacher Notes

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Jen has six potatoes on her plate. Three potatoes roll off. How many potatoes are left? We could also ask, "What is the difference in the number of potatoes we started with, and the number of potatoes left?"

6

Whole

3

(Rolled away) Part (Left) Part

How many potatoes are left?

Teacher Notes

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There are 5 dogs in the park. 3 dogs ran away. How many dogs are left?

Whole Part Part

How many dogs are left?

Teacher Notes

SLIDE 3

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5 3 ________ dogs ran away dogs left We can use counters to help us solve subtraction problems.

Using Counters Slide 11 (Answer) / 188

5 3 ________ dogs ran away dogs left We can use counters to help us solve subtraction problems.

Using Counters

Teacher Notes

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Pull down the counters to represent the dogs. Continue using the counters on the new few pages. Also have students use real counters at their desks.

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8 apple pies 2 pies are eaten ______ pies left

Let's Show it With Counters Slide 13 / 188 Let's Practice

10 balloons 5 blow away ______ balloons are left

Slide 14 / 188 Let's Practice

3 leaves on a tree 3 leaves fall off ______ leaves left

Slide 15 / 188 Let's Practice

6 take away 1 _____ left

SLIDE 4

Slide 16 / 188 Let's Practice

8 take away 3 _____ left

Slide 17 / 188 Let's Practice

9 take away 5 _____ left

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We can also use connecting cubes to help us subtract. Each cube represents an object. To show subtraction, remove the amount taken away. 2 1 ________ blue birds flies away birds left

Connecting Cubes Slide 18 (Answer) / 188

We can also use connecting cubes to help us subtract. Each cube represents an object. To show subtraction, remove the amount taken away. 2 1 ________ blue birds flies away birds left

Connecting Cubes

Teacher Notes

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Pull down linking cubes to represent an object. Line up the cubes so that they look like they are connected. Have students use cubes at their desks.

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5 apples 3 are rotten _____ apples left 7 rakes 2 break _____ rakes left

Let's Practice Slide 20 / 188 1 7 dogs are outside and 3 run away. There are 10 dogs in all. Yes No

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Slide 20 (Answer) / 188 1 7 dogs are outside and 3 run away. There are 10 dogs in all. Yes No

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Answer

No Slide 21 / 188 2 3 cats and 3 run away. _____ cats left A 5 B 6 C 0 Slide 21 (Answer) / 188 2 3 cats and 3 run away. _____ cats left A 5 B 6 C 0

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Answer

Slide 22 / 188 3 4 rakes and 2 break. _____ rakes left A 2 B 6 C 8 Slide 22 (Answer) / 188 3 4 rakes and 2 break. _____ rakes left A 2 B 6 C 8

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Answer

A Slide 23 / 188 4 3 pumpkins and 2 roll away. ____ pumpkins left

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Slide 23 (Answer) / 188 4 3 pumpkins and 2 roll away. ____ pumpkins left

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Answer

1 Slide 24 / 188 5 8 hats and 3 blow away. _____ hats left Slide 24 (Answer) / 188 5 8 hats and 3 blow away. _____ hats left

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Answer

5 Slide 25 / 188 Slide 26 / 188 Slide 27 / 188

Subtraction Sentences

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SLIDE 7

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8 minus 2 equals 6 1 2 3 4 5 6

x x

Subtraction Sentences Slide 29 / 188

The minus sign means to take away.

The Minus Sign

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A subtraction sentence has 2 parts, a minus sign, an equal sign and a whole.

8 - 2 = 6

Parts Minus Sign Equal Sign Whole

Subtraction Sentence Parts Slide 31 / 188

Slide the labels to the correct part of the subtraction sentence.

3 - 1 = 2

Parts Minus Sign Equal Sign Whole

Subtraction Sentence Parts Slide 31 (Answer) / 188

Slide the labels to the correct part of the subtraction sentence.

3 - 1 = 2

Parts Minus Sign Equal Sign Whole

Subtraction Sentence Parts

[This object is a pull tab] Math Practice

MP 6 Attend to precision Give students time to think about the different parts of a subtraction sentence. Then call on different students to come to the board to label the different parts. It is important for them to recognize what each part represents.

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Slide the labels to the correct part of the subtraction sentence.

9 - 4 = 5

Parts Minus Sign Equal Sign Whole

Subtraction Sentence Parts

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The first number is the largest number. It is called the minuend.

8 - 6 = 2

Minuend

The Minuend Slide 34 / 188

The second number tell us how many we are taking away. This is called the subtrahend.

8 - 6 = 2

Subtrahend

The Subtrahend Slide 35 / 188

The answer is called the difference. Will the difference be greater or less than the minuend?

8 - 6 = 2

Difference

The Difference Slide 35 (Answer) / 188

The answer is called the difference. Will the difference be greater or less than the minuend?

8 - 6 = 2

Difference

The Difference

[This object is a pull tab] Math Practice

MP 2 Reason abstractly and quantitatively. Ask students if the difference will be greater than or less than the

minuend. Have them

explain why.

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Subtraction sentences can be written with the difference on the left or right of the equal sign.

11 - 7 = 4 4 = 11 - 7

Difference Difference

Left or Right Slide 37 / 188

Subtraction sentences can also be written top to bottom.

11 - 7 = 4

11

7

4

Difference

Top to Bottom

SLIDE 9

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See Write 4 - 3 = 1 Say

4 minus 3 equals 1

x x x

See, Write and Say Slide 39 / 188

3 - 2 = 1

1 2 3 Slide 39 (Answer) / 188

3 - 2 = 1

1 2 3

Teacher Notes

[This object is a teacher notes pull tab] Read the following story to the students and have students act it out (change names for your students): Joe, Cole, and Drew are on the hay ride. How many students are on the hay ride? (When the students say "3", click the first gray box down to reveal the number 3.) Drew and Joe got off. How many kids got off? (When the students say "2", click the second box to reveal - 2). How many children are left on the hay ride? (Click the last box to show = 1). Then explain that this is one way to write about the story we just acted out. It says "3 - 2 = 1". Three children take away two children leaves one child left. Continue to work through the examples on the next few pages.

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9

5

4

1 2 3 Slide 40 (Answer) / 188

9

5

4

1 2 3

Teacher Notes

[This object is a teacher notes pull tab] Nine crows are sitting on a fence. Five fly

away. How many crows are left?

Remember to allow students that are not acting out the story to use cubes or counters to represent the crows. Also, remember to read the subtraction sentence back to the students as "9 crows minus 5 crows equals 4 crows." This will help them connect the symbol to real

bjects.

6- 1 = 5

1 2 3

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6- 1 = 5

1 2 3

Teacher Notes

[This object is a teacher notes pull tab] 6 pumpkins are on the truck. 1 rolled off the

truck. How many pumpkins are left?

Remember to allow students that are not acting out the story to use cubes or counters to represent the pumpkins. Also, remember to read the subtraction sentence back to the students as "6 pumpkins minus 1 pumpkin equals 5 pumpkins left." This will help them connect the symbol to real

bjects.

2

2

1 2 3 Slide 42 (Answer) / 188

2

2

1 2 3

Teacher Notes

[This object is a teacher notes pull tab] 2 scarecrows are in the field. The farmer takes 2 scarecrows down. How many scarecrows are left? Remember to allow students that are not acting out the story to use cubes or counters to represent the scarecrows. Also, remember to read the subtraction sentence back to the students as "2 scarecrows minus 2 scarecrows equals 0 scarecrows." This will help them connect the symbol to real objects. Also read the sentence as "2 - 2 = 0"

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9 - 3 = 6

1 2 3 Slide 43 (Answer) / 188

9 - 3 = 6

1 2 3

Teacher Notes

[This object is a teacher notes pull tab] 9 leaves are on a tree. 3 fall off. How many leaves left on the tree? Remember to allow students that are not acting out the story to use cubes or counters to represent the leaves. Also, remember to read the subtraction sentence back to the students as "9 leaves minus 3 leaves equals 6 leaves left." This will help them connect the symbol to real objects. Also, read the sentence as "9-6=3"

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8

2

6

3 2 1

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8

2

6

3 2 1

Teacher Notes

[This object is a teacher notes pull tab] 8 corn stalks grew tall. 2 corn stalks fell

ver. How many corn stalks are left?

Remember to allow students that are not acting out the story to use cubes or counters to represent the corn stalks. Also, remember to read the subtraction sentence back to the students as "8 corn stalks minus 2 corn stalks equals 6 corn stalks". This will help them connect the symbol to real objects. Also read the sentence as "8-2=6"

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Teacher Notes

[This object is a teacher notes pull tab] Allow students to make up their own stories and share them as a class. As

ne student tells a story, have another

student write the subtraction sentence on the board. Then allow another student to read the sentence at the end. Continue making up stories until you feel that students have a good understanding.

Slide 46 / 188 6 Which subtraction sentence matches this story? Six kids are playing. Four kids go home. Now there are two kids left. A 6 -2 = 4 B 6 - 4 = 10 C 6 - 4 = 2 Slide 46 (Answer) / 188 6 Which subtraction sentence matches this story? Six kids are playing. Four kids go home. Now there are two kids left. A 6 -2 = 4 B 6 - 4 = 10 C 6 - 4 = 2

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Answer

C Slide 47 / 188 7 Which subtraction sentence matches this story? Five pumpkins are on the table. The farmer sells two. There are three pumpkins left. A 5 - 3 = 2 B 5 - 2 = 3 C 5 - 2 = 7

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Slide 47 (Answer) / 188 7 Which subtraction sentence matches this story? Five pumpkins are on the table. The farmer sells two. There are three pumpkins left. A 5 - 3 = 2 B 5 - 2 = 3 C 5 - 2 = 7

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Answer

B Slide 48 / 188 8 Which subtraction sentence matches this story? Six balloons are tied on the fence. Five pop. 1 balloon is left. A 6 - 5 = 1 B 6 - 1 = 5 C 6 - 5 = 2 Slide 48 (Answer) / 188 8 Which subtraction sentence matches this story? Six balloons are tied on the fence. Five pop. 1 balloon is left. A 6 - 5 = 1 B 6 - 1 = 5 C 6 - 5 = 2

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Answer

A Slide 49 / 188 9 Which subtraction sentence matches this story? Ten chickens are at the farm. Four fly away. How many chickens are left? A 10 - 6 = 4 B 10 - 4 = 6 C 10 - 4 = 5 Slide 49 (Answer) / 188 9 Which subtraction sentence matches this story? Ten chickens are at the farm. Four fly away. How many chickens are left? A 10 - 6 = 4 B 10 - 4 = 6 C 10 - 4 = 5

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Answer

B Slide 50 / 188 10 Which subtraction sentence matches this story? Thirteen pieces of candy are on the table. Jen eats 5 pieces. There are 8 pieces left. A 13 - 8 = 5 B 13 - 5 = 7 C 13 - 5 = 8

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Slide 50 (Answer) / 188 10 Which subtraction sentence matches this story? Thirteen pieces of candy are on the table. Jen eats 5 pieces. There are 8 pieces left. A 13 - 8 = 5 B 13 - 5 = 7 C 13 - 5 = 8

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Answer

C Slide 51 / 188 Slide 52 / 188 Slide 53 / 188

Number Stories

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When looking at a subtraction word problem, we need to figure out if the numbers we know show the whole number of things or the parts.

Word Problems Slide 55 / 188

Jim has 8 pennies. His mom takes 2 away. How many pennies does Jim have left? Underline what we know. Circle what we want to know.

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Story 1: Pennies

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Jim has 8 pennies. His mom takes 2 away. How many pennies does Jim have left? Underline what we know. Circle what we want to know.

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Story 1: Pennies

[This object is a pull tab] Teacher Notes & Math Practice MP 4 Model with Mathematics Read the entire story and then underline the first two lines to show that this is the information we KNOW. Then circle the last line to show that this is what we want to know. Point out the question mark at the end and remind the students that this tells us that they are asking us something. Next, guide the students to write a subtraction sentence to solve the problem. Have them go back and check that their sentence matches the story and that the subtraction sentence, makes sense (the first number must be the biggest).

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There are 5 cats on the fence. 1 jumps down. How many cats are left on the fence? Underline what we know. Circle what we want to know.

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Story 2: Cats

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There are 5 cats on the fence. 1 jumps down. How many cats are left on the fence? Underline what we know. Circle what we want to know.

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Story 2: Cats

Teacher Notes

[This object is a teacher notes pull tab] Then circle the last line to show that this is what we want to know. Point out the question mark at the end and remind the students that this tells us that they are asking us something. Next, guide the students to write a subtraction sentence to solve the problem. Have them go back and check that their sentence matches the story and that the subtraction sentence, makes sense (the first number must be the biggest). Read the entire story and then underline the first two lines to show that this is the information we KNOW.

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There are 4 people at the farm. 2 people leave the farm. How many people are left at the farm? Underline what we know. Circle what we want to know.

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Story 3: People

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There are 4 people at the farm. 2 people leave the farm. How many people are left at the farm? Underline what we know. Circle what we want to know.

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Story 3: People

Teacher Notes

[This object is a teacher notes pull tab] Then circle the last line to show that this is what we want to know. Point out the question mark at the end and remind the students that this tells us that they are asking us something. Next, guide the students to write a subtraction sentence to solve the problem. Have them go back and check that their sentence matches the story and that the subtraction sentence, makes sense (the first number must be the biggest). Read the entire story and then underline the first two lines to show that this is the information we KNOW.

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10 - 7 =

Make up a story for this number sentence.

Let's Make up a Story

SLIDE 15

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6

3

Make up a story for this number sentence.

Let's Make up a Story Slide 60 / 188 Class Activity

Student made subtraction stories

Slide 60 (Answer) / 188 Class Activity

Student made subtraction stories

Teacher Notes

[This object is a teacher notes pull tab] At this point students may be ready to increase the subtrahend to as much as 20. The "Take Away" model has been used up to this point and other subtraction models will be introduced as well. Drawing and/or using manipulatives will be an important strategy at this point as well. This next lesson is to help students make connections to number sentences. Split the students into small groups. Have each group first think of a subtraction

sentence. Next have them come up with a

story to match their sentence. Call on different groups to act out their story for the class.

Slide 61 / 188 11 There are 8 ants on a log. 3 crawl off. How many ants are left on the log? A 4 B 5 C 6 Slide 61 (Answer) / 188 11 There are 8 ants on a log. 3 crawl off. How many ants are left on the log? A 4 B 5 C 6

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Answer

B Slide 62 / 188 12 There are 8 ducks in the pond. 3 swim away. How many ducks are left in the pond?

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Slide 62 (Answer) / 188 12 There are 8 ducks in the pond. 3 swim away. How many ducks are left in the pond?

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Answer

5 Slide 63 / 188 13 You have 12 pencils on your box. 6 of the pencils break. How many pencils are left in all? A 4 B 5 C 6 Slide 63 (Answer) / 188 13 You have 12 pencils on your box. 6 of the pencils break. How many pencils are left in all? A 4 B 5 C 6

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C Slide 64 / 188 14 There are 9 hippos in a pond. 5 of them get out. How many hippos are still in the pond? Slide 64 (Answer) / 188 14 There are 9 hippos in a pond. 5 of them get out. How many hippos are still in the pond?

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4 Slide 65 / 188 15 You see 11 cookies in a box. Nine of them are chocolate chip. How many are not chocolate chip? A 4 B 2 C 3

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Slide 65 (Answer) / 188 15 You see 11 cookies in a box. Nine of them are chocolate chip. How many are not chocolate chip? A 4 B 2 C 3

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Answer

B Slide 66 / 188 Slide 67 / 188 Slide 68 / 188

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Comparing Groups

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How many cubes are in each train? ______ ______

Comparing Slide 70 / 188

6 4 Which number is more? Circle it You can subtract to compare groups

Comparing

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6 4 ______ - ______ = ______ We know that there are more blue blocks than green

blocks. If we want to know how many more blue blocks

we can subtract. The bigger number is written first and then subtract the smaller number.

Comparing Slide 71 (Answer) / 188

6 4 ______ - ______ = ______ We know that there are more blue blocks than green

blocks. If we want to know how many more blue blocks

we can subtract. The bigger number is written first and then subtract the smaller number.

Comparing

Teacher Notes

[This object is a teacher notes pull tab] Complete the subtraction number sentence as you work through this page.

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How much less? How much more? How much shorter? How much taller? How many fewer? How many more? How much smaller? How much larger? How much further? How much closer?

Comparing Words Slide 73 / 188

______ - ______ = ______ The bigger number is written first and then subtract the smaller number. ______ ______

Comparing Slide 73 (Answer) / 188

______ - ______ = ______ The bigger number is written first and then subtract the smaller number. ______ ______

Comparing

Teacher Notes

[This object is a teacher notes pull tab] Complete the subtraction number sentence as you work through this page.

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______ - ______ = ______ The bigger number is written first and then subtract the smaller number. ______ ______

Comparing

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Slide 74 (Answer) / 188

______ - ______ = ______ The bigger number is written first and then subtract the smaller number. ______ ______

Comparing

Teacher Notes

[This object is a teacher notes pull tab] Complete the subtraction number sentence as you work through this page.

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There are 8 monkeys at the zoo. There are 12 zebras at the zoo. How many more monkeys than zebras? ______ - ______ = ______

Monkeys and Zebras Slide 77 / 188

If you do not have cubes or pictures, draw circles to help. There are 6 elephants. There are 2 lions. How many fewer lions? E L ______ - ______ = ______ Draw a line to see what is left behind.

Using Circles Slide 78 / 188

If you do not have cubes or pictures, draw circles to help. There are 10 tigers. There are 6 cheetahs. How many more tigers? ______ - ______ = ______ Draw a line to see what is left behind.

Using Circles Slide 79 / 188

The worm is 6 inches. The snake is 14 inches long. How much shorter is the worm? ______ - ______ = ______

Using Circles

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Slide 79 (Answer) / 188

The worm is 6 inches. The snake is 14 inches long. How much shorter is the worm? ______ - ______ = ______

Using Circles

[This object is a pull tab] Math Practice

MP 1 Make sense of problems and persevere in solving them Have students identify what the problem is asking before writing the subtraction

sentence. Have them explain

how they will solve it as well.

Slide 80 / 188 16 How many more green cubes than blue cubes? A 1 B 4 C 3 Slide 80 (Answer) / 188 16 How many more green cubes than blue cubes? A 1 B 4 C 3

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C Slide 81 / 188 17 How many fewer red cubes than blue cubes? Slide 81 (Answer) / 188 17 How many fewer red cubes than blue cubes?

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4 Slide 82 / 188 18 There are 10 bears. There are 2

tigers. How many more bears?

A 12 B 8 C 10

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Slide 82 (Answer) / 188 18 There are 10 bears. There are 2

tigers. How many more bears?

A 12 B 8 C 10

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B Slide 83 / 188 19 8 is 5 more than 3 True False Slide 83 (Answer) / 188 19 8 is 5 more than 3 True False

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True Slide 84 / 188 20 Beth saw 4 birds. Jim saw 10 birds. How many fewer did Beth see? Slide 84 (Answer) / 188 20 Beth saw 4 birds. Jim saw 10 birds. How many fewer did Beth see?

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Answer

6 Slide 85 / 188

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Slide 86 / 188 Slide 87 / 188

Subtraction on a Number Line

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Slide 87 (Answer) / 188

Subtraction on a Number Line

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Teacher Notes

[This object is a teacher notes pull tab] Before starting this lesson be sure that each student has a number line on his/her desk. If needed, do a quick review about the number line and how to use it.

Slide 88 / 188 Class Activity: Bead Number Line Slide 88 (Answer) / 188 Class Activity: Bead Number Line

Teacher Notes

[This object is a teacher notes pull tab] Supplies:

1 pipe cleaner per child
1 number line print out on card stock (laminated is

best)

1 pony bead per child

Directions:

Print out one number line per child and laminate it.
Make a small hole before the 0 and after 20
Have student slide one pony bead onto one pipe

cleaner.

Have student slide one end of the pipe cleaner into

each hole on the number line.

Bend the ends behind the paper.
Practice having students move the bead to a given

number by sliding it along the pipe cleaner.

Slide 89 / 188 Class Activity Floor Number Line

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1

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

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Slide 89 (Answer) / 188 Class Activity Floor Number Line

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1

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Teacher Notes

[This object is a teacher notes pull tab] ~ Make one set of number cards by writing each number from 0-20 on a sheet of paper. ~ Tape the number cards on the floor to make a large number line. ~ Have each student use their bead line at their desks. ~ Have a student stand on the number 5 on the floor number line. Have the student take 3 steps back. Count the three steps aloud. Have students model counting back 3 from 5 at their seats. ~ Write and discuss the subtraction sentence that matches. ~ Repeat with more problems.

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We can use a number line to find the difference between two numbers (subtract). 5 - 3 = _____ The minuend tells us where to start. The subtrahend tells us how many jumps to take back. The difference (answer) of the two numbers is where we end.

Starting number Number of jumps back Where did you end?

1 2 3 4 5 6 7 8 9 10 111213 1415 16171819 20

Using a Number Line Slide 91 / 188

Sometimes it helps to circle the minuend to help us remember where to start.

5 - 3 = _____

Don't forget to start counting after you jump!! 1 2 3 1 2 3 4 5 6 7 8 9 10 111213 1415 16171819 20 Remember where to start

Using a Number Line Slide 92 / 188 9 - 4 = _____

What number should we circle? How many jumps back will we take? Where did we land?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Using a Number Line Slide 93 / 188

What number should we circle? How many jumps back will we take? Where did we land?

11 - 8 = _____

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Using a Number Line Slide 94 / 188 21 6 - 1 = 7 Yes No

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Slide 94 (Answer) / 188 21 6 - 1 = 7 Yes No

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No Slide 95 / 188 22 5 - 3 = 2 Yes No Slide 95 (Answer) / 188 22 5 - 3 = 2 Yes No

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Yes Slide 96 / 188 23 3 - 3 = ____ A 6 B 1 C 0 Slide 96 (Answer) / 188 23 3 - 3 = ____ A 6 B 1 C 0

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C Slide 97 / 188 24 17 - 2 = _____

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Slide 97 (Answer) / 188 24 17 - 2 = _____

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15 Slide 98 / 188 25 16 - 7 = _____ Slide 98 (Answer) / 188 25 16 - 7 = _____

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9 Slide 99 / 188 Slide 100 / 188 Slide 101 / 188

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Subtraction on a Number Grid

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Slide 101 (Answer) / 188

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Subtraction on a Number Grid

Teacher Notes

[This object is a teacher notes pull tab] Before starting this lesson be sure that each student has a number grid on his/her desk. If needed, do a quick review about the number grid and how to use it.

Slide 102 / 188

We can use a number grid to help us subtract as well.

Using a Number Grid Slide 103 / 188

The minuend tells us where to start. The subtrahend tells us how many jumps to take back. The difference between the two numbers (answer) is where we end.

12 - 7 = ____ Using a Number Grid Slide 104 / 188 19 - 6 = ____ Using a Number Grid Slide 105 / 188

Look at the subtraction sentence. Where will we start on the number grid? How many jumps will we take?

14 - 3 = ____

** Just like on a number line, don't count until you jump **

Using a Number Grid Slide 106 / 188 14 - 4 = ____

What should we do when we get to the last number in a row?

Using a Number Grid

SLIDE 27

Slide 107 / 188 17 - 8 = ____ Using a Number Grid Slide 107 (Answer) / 188 17 - 8 = ____ Using a Number Grid

[This object is a pull tab] Math Practice

MP 5 Use appropriate tools strategically Ask students to explain to a partner how to use a number grid to subtract. Then have a student come to the board to model it.

Slide 108 / 188 20 - 5 = ____ Using a Number Grid Slide 109 / 188 7 - 6 = ____ Using a Number Grid Slide 110 / 188 26 11 - 6 = 5 True False Slide 110 (Answer) / 188 26 11 - 6 = 5 True False

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Answer

True

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Slide 111 / 188 27 16 - 9 = _____ A 6 B 2 C 7 Slide 111 (Answer) / 188 27 16 - 9 = _____ A 6 B 2 C 7

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Answer

C Slide 112 / 188 28 17 - 7 = _____ A 10 B 14 C 0 Slide 112 (Answer) / 188 28 17 - 7 = _____ A 10 B 14 C 0

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Answer

A Slide 113 / 188 29 18 - 9 = _____ Slide 113 (Answer) / 188 29 18 - 9 = _____

[This object is a pull tab]

Answer

9

SLIDE 29

Slide 114 / 188 30 13 - 8 = _____

QUIZ

Slide 114 (Answer) / 188 30 13 - 8 = _____

QUIZ [This object is a pull tab]

Answer

5 Slide 115 / 188 Slide 116 / 188 Slide 117 / 188

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Subtracting Zero

Slide 118 / 188

Amy had 8 pieces of candy. She decides to eat 0 pieces. How many pieces of candy are left?

SLIDE 30

Slide 119 / 188

What do we need to find out? What information do we know? How can we show this problem with counter?

Let's work through it! Slide 119 (Answer) / 188

What do we need to find out? What information do we know? How can we show this problem with counter?

Let's work through it!

Teacher Notes

[This object is a teacher notes pull tab] Use the bottom of this page to work through the problem. Discuss what 0 means.

Slide 120 / 188

When you subtract 0, you have the same number left.

5 - 0 = 5

Slide 121 / 188

How would we show taking away zero with counters?

6 - 0 =

Slide 122 / 188

How would we show subtracting zero with cubes?

9 - 0 =

Slide 123 / 188

Remember since we are not taking away any cubes or counters, the answer is the same as the first number.

13 - 0 = 13

SLIDE 31

Slide 123 (Answer) / 188

Remember since we are not taking away any cubes or counters, the answer is the same as the first number.

13 - 0 = 13

[This object is a pull tab] Math Practice

MP 7 Look for and make use

f structure.

Ask students how subtracting 0 is like adding 0.

Slide 124 / 188

19 - 0 = ______ 11 - 0 = ______ 6 - 0 = ______ 14 - 0 = ______

Find the difference Slide 125 / 188 31 9 - 0 = 9 True False Slide 125 (Answer) / 188 31 9 - 0 = 9 True False

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Answer

True Slide 126 / 188 32 4 - 0 = ______ A 40 B 4 C 0 Slide 126 (Answer) / 188 32 4 - 0 = ______ A 40 B 4 C 0

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Answer

B

SLIDE 32

Slide 127 / 188 33 6 - 0 = ____ Slide 127 (Answer) / 188 33 6 - 0 = ____

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Answer

6 Slide 128 / 188 34 10 - 0 = _____ Slide 128 (Answer) / 188 34 10 - 0 = _____

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Answer

10 Slide 129 / 188 35 17 - 0 = _____ Slide 129 (Answer) / 188 35 17 - 0 = _____

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Answer

17

SLIDE 33

Slide 130 / 188 Slide 131 / 188 Slide 132 / 188

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Subtract All

Slide 133 / 188 Class Activity: Simon Says Slide 133 (Answer) / 188 Class Activity: Simon Says

Teacher Notes

[This object is a teacher notes pull tab] Play a quick game of Simon Says with the students. Make all the commands involve "all".

Simon says for all the boys to stand all.
Simon says put all your hands on your desk.
Simon says all the students sit down.
Simon says for all the girls to turn around.
Simon says put all fingers on you knee.
Simon says take all your fingers off your knee.

Continue playing for a few minutes. Ask the students if they noticed any patterns. Discuss the word all and what it means.

Slide 134 / 188

When the minuend and the subtrahend are the same, you are subtracting all.

17 - 17 = 0

Same

9 - 9 = 0

Same

SLIDE 34

Slide 135 / 188

When you subtract all, you have 0 left.

xxxx

4 - 4 = 0

The first two numbers are the same in a subtract all problem.

Slide 136 / 188

How would we show taking away all with counters?

7 - 7 =

Slide 137 / 188

8 - 8 = _____

Cover the counters to show how many you will take away.

Slide 138 / 188

12 - 12 = ___

Cover the counters to show how many you will take away.

Slide 139 / 188

17 - 17 = ___

Cover the counters to show how many you will take away.

Slide 140 / 188

2 - 2 = ___

Cover the counters to show how many you will take away.

SLIDE 35

Slide 141 / 188

5 - 5 = ___

Use counters to demonstrate if necessary.

Let's Practice Slide 142 / 188

14 - 14 = ____

Slide 143 / 188

11 - 11 = ____

Slide 144 / 188

16 - 16 = ____

Slide 145 / 188 Sort the Subtraction Sentences Slide 146 / 188 Class Discussion

Jen told her dad that 6 - 6 is a doubles fact and the answer is 12. Is Jen correct? Explain

SLIDE 36

Slide 147 / 188 36 12 - 12 = _____ Slide 147 (Answer) / 188 36 12 - 12 = _____

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Answer

Slide 148 / 188 37 Does 9 - 9 = 0? Yes No Slide 148 (Answer) / 188 37 Does 9 - 9 = 0? Yes No

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Answer

Yes Slide 149 / 188 38 4 - 4 = _____ Slide 149 (Answer) / 188 38 4 - 4 = _____

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Answer

SLIDE 37

Slide 150 / 188 39 14 - 14 = A 0 B 14 C 28 Slide 150 (Answer) / 188 39 14 - 14 = A 0 B 14 C 28

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Answer

A Slide 151 / 188 40 7 - 7 = _____ Slide 151 (Answer) / 188 40 7 - 7 = _____

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Answer

Slide 152 / 188 Slide 153 / 188

SLIDE 38

Slide 154 / 188

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Subtracting 1, 2, or 3

Slide 154 (Answer) / 188

Click to return to Table of Contents

Subtracting 1, 2, or 3

Teacher Notes

[This object is a teacher notes pull tab] Students are expected to be able to count backwards for this lesson. There are extra practice worksheets in the teacher resources if you feel that your students need them.

Slide 155 / 188 Class Activity Slide 155 (Answer) / 188 Class Activity

Teacher Notes

[This object is a teacher notes pull tab] Practice counting backwards starting at different numbers between 1-20. Some ideas:

Stand tall like a rocket and get smaller as they

count down to blast off

March like a soldier while counting back
Jump like a diver on a diving board while counting

back

Slide 156 / 188 Class Activity Counting Back Songs

10 in a Bed 10 Little Monkeys Jumping on the Bed 5 Little Ducks

Slide 156 (Answer) / 188 Class Activity Counting Back Songs

10 in a Bed 10 Little Monkeys Jumping on the Bed 5 Little Ducks

Teacher Notes

[This object is a teacher notes pull tab] Practice singing songs that focus on counting back. The three songs listed are linked to www.YouTube.com to allow the children to have a visual to go with the song.

SLIDE 39

Slide 157 / 188

Counting backwards can help us subtract.

8 - 3 = 5

7 6 5

Counting Backwards Slide 158 / 188

Counting backwards can help us subtract.

6 - 2 = 4

5 4

Counting Backwards Slide 159 / 188

4 - 1 = 3

Try to picture a number line in your head. Find the first number, then jump back.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Counting Backwards Slide 160 / 188

Try to picture a number line in your head.

7 - 3 = __

What number will you start at? How many jumps will you back take?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Counting Backwards Slide 161 / 188 5 - 1 = _____ 12 - 2 = _____ Let's Practice 9 - 3 = _____ 15 - 3 = _____ 2 - 2 = _____ 17 - 1 = _____ Slide 162 / 188

We can use cubes to help us count back. To show - 1, take away one cube. 3 - 1 =

Let's Practice

SLIDE 40

Slide 163 / 188

Your mom gave you five cookies. Then she took two away. How many are left?

5 - 2 = Let's Practice Slide 164 / 188

You picked 9 flowers. You gave one away. How many are left?

9 - 1 = Let's Practice Slide 165 / 188

Your sister has 12 crayons. She gave 3 away. How many are left?

12 - 3 = Let's Practice Slide 166 / 188 Class Discussion

How can you count back to solve 15 - 3?

Slide 167 / 188 41 14 - 1 = Slide 167 (Answer) / 188 41 14 - 1 =

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Answer

13

SLIDE 41

Slide 168 / 188 42 17 - 3 = Slide 168 (Answer) / 188 42 17 - 3 =

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Answer

14 Slide 169 / 188 43 4 - 2 = Slide 169 (Answer) / 188 43 4 - 2 =

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Answer

2 Slide 170 / 188 44 18 - 2 = Slide 170 (Answer) / 188 44 18 - 2 =

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Answer

16

SLIDE 42

Slide 171 / 188 45 5 - 2 = Slide 171 (Answer) / 188 45 5 - 2 =

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Answer

3 Slide 172 / 188 Slide 173 / 188 Slide 174 / 188

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Subtracting Ten

Slide 175 / 188

Subtracting 10 is very easy when using a number grid. Find the minuend on the number grid and move up one box.

Subtracting 10

SLIDE 43

Slide 176 / 188

14 - 10 = 4

Subtracting 10 Slide 176 (Answer) / 188

14 - 10 = 4

Subtracting 10

Teacher Notes

[This object is a teacher notes pull tab] Discuss why 14 is circled. Allow students to count the boxes one jump at a time to confirm that one jump up is the same as ten jumps.

Slide 177 / 188

16 - 10 =

Let's Practice Slide 178 / 188

12 - 10 =

Let's Practice

What number would you circle?

Slide 179 / 188

18 - 10 =

Let's Practice

What number would you circle?

Slide 180 / 188

10 - 10 =

Let's Practice

What number would you circle?

SLIDE 44

Slide 181 / 188 46 Does 15 - 10 = 5 ? Yes No Slide 181 (Answer) / 188 46 Does 15 - 10 = 5 ? Yes No

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Answer

Yes Slide 182 / 188 47 19 - 10 = 19 True False Slide 182 (Answer) / 188 47 19 - 10 = 19 True False

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Answer

False Slide 183 / 188 48 18 - 10 = A 18 B 81 C 8 Slide 183 (Answer) / 188 48 18 - 10 = A 18 B 81 C 8

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Answer

C

SLIDE 45

Slide 184 / 188 49 16 - 10 = Slide 184 (Answer) / 188 49 16 - 10 =

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Answer

6 Slide 185 / 188 50 14 - 10 = Slide 185 (Answer) / 188 50 14 - 10 =

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Answer

4 Slide 186 / 188 Slide 187 / 188

SLIDE 46

Slide 188 / 188