2-Digit Subtraction Without Regrouping Click to return to - - PDF document
Slide 1 / 137 Slide 2 / 137 2nd Grade 2 Digit Addition and Subtraction 2015-12-03 www.njctl.org Slide 3 / 137 Table of Contents Presentation 2 click on a topic to go to that section Mentally adding and subtracting 10 and 100 Addition
2015-12-03 www.njctl.org
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Addition Subtraction Mixed Addition and Subtraction Practice Mentally adding and subtracting 10 and 100 Lab: Give and Take
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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2 Digit Subtraction without Regrouping Regrouping with Base Ten Blocks Subtraction Word Problems with Regrouping Subtraction Practice
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2 Digit Word Problems without Regrouping Regrouping without Base Ten Blocks
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What number is shown?
Now we want to subtract 14. When we subtract, we take away. ALWAYS start with the bigger number when you subtract.
tens ones
two numbers.
The ones are stacked and so are the tens.
tens ones
by crossing them out. How many are left?
tens ones
How many are left?
tens ones
What number is shown?
Let's subtract 20 Our subtraction number model is:
tens ones
What do we subtract first?
tens ones
What is the next step?
tens ones
If there is not a place value chart, it may help to draw a line between the tens and ones to keep them seperated.
What should we do to this subtraction problem to make it easier to answer?
1 If you take away 70, is the answer 24? Yes No
2 If you take 12 away from this number, is the difference 7? Yes No
3 Take away 83. What is the difference?
4 Take 32 away from this number, what is the difference?
5 What is the difference 67 - 47 = ?
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There are 24 children in a play. 11 children dance. The other children sing. How many children sing?
How many singers? 24 children in all There are 24 children in a play. 11 children dance. The other children sing. How many children sing? 11 dancers
To find the difference, subtract:
Remember:
Where is the bigger number in each problem?
How can we find the answer? There are 37 chairs at the play. There are 13 couches. How many more chairs than couches are there?
Zachary sold 28 tickets for the play. Patrick sold 15 tickets. How many more tickets did Zachary sell than Patrick?
On Friday, 49 people came to the play. On Saturday, 25 fewer people came. How many came on Saturday?
6 There are 28 girls and 16 boys in the class. How many more girls than boys are in the class? A 12 B 14 C 36 D 46
7 Britney sold 39 boxes of popcorn and 18 sodas. How many more boxes of popcorn than sodas did she sell? A 11 B 18 C 21 D 26
8 There are 34 geese and 24 ducks in a pond. How many more geese than ducks are there?
9 There are 41 seagulls on the beach. Then 30 fly
10 Henry has 45 stamps. He gives 13 to Julie. How many stamps does he have left?
Quiz
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What number is shown?
33 - 8 = ? Now we want to subtract 8. What do we do first?
How can we get more ones without changing the total number? We have to take 8 ones away, but we do not have enough.
33 - 8 = Now you can subtract!!! Cross out the ones that you take away.
What is the difference?
52 - 7 = ? What do we need to do?
Look at the problem below. Do you need to regroup? How do you know? 63 - 9 = ?
Look at the problem below. First, decide is you need to regroup. 41 - 5 = ?
Look at the problem below. First, decide is you need to regroup. 83 - 2 = ?
Look at the problem below. First, decide is you need to regroup. 46 - 22 = ?
Look at the problem below. Draw base ten blocks to help you solve the problem. 35 - 7 = ?
Look at the problem below. Draw base ten blocks to help you solve the problem. 11 - 3 = ?
How will you know if you have to regroup?
11 Which TWO problems require you to regroup? A 57 - 3 = ? B 38 - 9 = ? C 13 - 5 = ? D 40 - 0 = ?
12 Do you need to regroup? 45 - 8 = ? Yes No
13 Do you need to regroup? 67 - 8 = ? Yes No
14 56
Use base ten blocks at your seat to help you
15 93
Use base ten blocks at your seat to help you
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tens ones
Look at the problem. What do we need to do first?
Before we subtract, we need to make sure the written problem matches the base ten blocks.
Before we subtract, we need to make sure the written problem matches the base ten blocks.
Can we take 7 away from 2? What do we need to do?
Base Ten Blocks
How can we solve this problem without base ten blocks?
Now let's subtract!
Remember! More on top? No need to stop! More on the floor? Go next door! Numbers the same? Zeros the name!
Change the columns to 2 prior to starting
Click on the picture below for more practice on the National Library of Virtual Manipulatives site.
16 85
48 Yes No
17 94 - 25 = 71 Yes No
18 67
19 88 - 34 =
20 42 - 7 =
21 34
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What do we have to do to find the answer? There are 65 students on the playground. 47 are wearing sneakers. How many are not wearing sneakers?
floor?"
tens ones
from 5, so we have to regroup 1 ten as 10
What do we do now?
tens ones
What is the next step?
One day 45 cars and 19 trucks were washed at the car wash. How many more cars than trucks were washed? What do we have to do to find the answer?
How do I subtract?
tens ones
There are 83 students eating lunch. 55 are eating hot lunch. How many students are not eating hot lunch?
A soda cost 75 cents. Mr. West has 46 cents. How many more cents does he need for a soda?
22 There are 50 students in the library. 27 of them are wearing blue. How many are not wearing blue? A 33 B 37 C 23 D 77
23 Colin had 32 baseball cards. He sold 16. How many were left?
24 Megan had 73 books at the yard sale. She sold 42. How many are left? A 31 B 115 C 211 D 35
25 The pet store has 58 fish. They sell 39 fish. How many fish are left at the pet store?
26 In art class, Jeff made 61 paper moons. Kelly made 9. How many more moons did Jeff make?
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How can we write this problem to find the difference? There are 84 apples on the apple tree. Sara picks 68
are left on the tree?
Do we have to regroup?
There is more on the floor. Regroup 1 ten for 10 ones Subtract the ones first, then the tens.
How do you know? What do we do first? What do we do next? Click each box to check your answer
Do we have to regroup?
There is more on top. Subtract the ones. Subtract the tens.
How do you know? What do we do first? What do we do next?
Click each box to check your answer
Jenna picks up 34 sea shells. She puts 17 of them in a box. How many does she have left?
Sadie buys 74 pieces of paper. She uses 44 for her book. How many pieces of paper are left?
27 Mom bakes 23 cupcakes. She decorates 19 purple and the rest blue. How many were blue? A 16 B 4 C 14 D 34
28 Becky buys 57 apples and oranges. 23 are
A 23 B 53 C 57 D 34 Pick the correct answer from each column to complete the subtraction sentence for this word problem. _______ - _______ = 34 E 23 F 53 G 57 H 34
29 Kira can jump a rope 94 times. Myah can jump a rope 79 times. How many more times can Kira jump than Myah?
30 The team scored 74 points. Shawn scored 36 of the points. How many points did the rest of the team score?
31 There are 49 markers in the box. 14 of them are being used. How many are left in the box?
Quiz
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There are 78 people wearing blue hats and 35 people wearing red
Addition The question asks how many in all Line up our numbers to add Is this an addition or subtraction problem? How do we know? What do we have to do to find the answer?
What do we add first?
Now what do we do?
Now what do we do?
The paint store has 64 cans of
many cans are left? Subtraction Is this an addition or subtraction problem? The problem talks about taking away and asks how many are left. How do we know? Line up the numbers, with the biggest number
What do we have to do to find the answer?
Click each box to check the answer
What clue words tell us what kind of problem this is? There are 50 blue birds and 86 red birds. How many birds are there all together?
Two boys collected a total of 43
many did Dave collect?
32 Kurt has 70 pennies. He gives Jay 48 pennies. How many pennies does he have left? A 38 B 22 C 118 D 32
33 Jenny does 29 jumping jacks. Nicole does 33 jumping jacks. How many jumping jacks did they do all together? A 52 B 16 C 62 D 4
34 There are 56 yellow flowers and 53 red flowers. How many flowers in all?
35 There are 38 kids that have brown eyes and 27 kids that have blue eyes. How many more kids have brown eyes?
36 Jack has to drive 82 miles. He already drove 47
drive?
Practice regrouping/ trading “tens” and “ones” while playing this game Click here for complete directions
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