Topic 6

Vocabulary

100

What does it mean to regroup?

To trade 1 ten for ten ones.

200

What is a sum?

The answer to an addition problem

300

What is a difference?

The answer to a subtraction problem.

400

In this equation what are the addends?

2+3=5

2 and 3

500

What is an equation?

Uses an equal sign to show that the value on the left is equal to the value on the right.

Regrouping

100

Do you need to regroup in this problem:

53-19=

Yes, because in the number 53, there are less ones than in the number 19. There are not enough ones to take 9 away.

200

Choose all of the problems that you will solve by regrouping:

27-9=?

53-4=?

81-2=?

76-5=?

27-9=?

53-4=?

81-2=?

300

In the problem 50-32=? do you have to regroup? Why or why not?

Yes, because there are no ones in the number 50. You can't take 2 away from nothing. The number in the ones place in 50 is smaller than the number in the ones place in 32.

400

Choose the problem you would have to use regrouping to solve. Explain how you know.

88-25=?  or 75-68=?

75-26=? Because the number in the ones place in 75 is smaller than the number in the ones place in 26. You can't take 6 away from 5 because there are not enough.

500

How do you know when you need to regroup?

You need to regroup when the number that is being subtracted has a bigger number in the ones place than the number that it is being subtracted from.

Example: 32-17=? Because the number that is being subtracted (17) has a bigger number in the ones place than the number that it is being subtracted from (32).

Subtraction problems

100

Solve:

32-24=?

8

200

Solve 59-23=?

36

300

Solve 40-23=?

17

400

Solve 33-19=?

14

500

Solve 55-21=?

34

Word Problems

100

Ethan has 62 Pokemon cards. He gives 28 to Riaan. How many Pokemon cards did he not give away? 

62-28=34

He did not give away 34 cards.

200

Manasa has 58 heart stickers. She also has 23 minion stickers. She gives 7 stickers away. How many stickers did she NOT give away?

Step 1. 58+23=81

Step 2. 81-7=74

She does not give away 74 stickers.

300

Anish has 58 books. Emily has 6 fewer books than Anish. Emily gives 8 books to Adya. How many books does Emily have now?

Step 1. 58-6=52

Step 2. 52-8=44

She has 44 books now.

400

CJ has 75 tickets to use at the fair. He uses 32 tickets in the morning. How many tickets are left?

75-32=43

43 tickets are left.

500

Josie makes 42 cookies for a bake sale. She sells 17 cookies on Monday. She sells 23 cookies on Tuesday. How many cookies does Josie have left to sell?

Which pair of equations can you use to solve the problem?

A. 42+17=59 and 59-23=36

B. 42-17=25 and 25-17=8

C. 17+23=40 and 42-40=2

D. 42+23=65 and 65-23=42

B. 42-17=25 and 25-17=8