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Properties of Addition
Addition and subtraction are related
Strip diagram
Estimate by Rounding
estimate sum and estimate difference
700

Mario wrote this number sentence.

48+(15+5)=(48+5)+15

What property of addition did Mario model?

Associative Property of Addition

700

David found 556-323. His answer is 233. Show how can you check your answer?

  233

+323

______

   556

700

What do we put on the line segment in a strip diagram? What do we put in the rectangles in a strip diagram?

Total on line segment

Parts or addends on the line segment

700

A pet store has 385 cats. At the end of the month, there were152 pets. Which is the most reasonable estimate for how many pets were sold?

240

700

387 + 251

638?

800
This property states that you can change the order of the addends and still get the same sum.
What is the Commutative Property of Addition?
800

Ramy found 384+215=599. How ca he check his answer? 

Subtract 599-215

800

Lara bought 253 video games last year. She gave some of the video games to her friend Amany. Now she has 162 left with him. How many games were given to Amany?

                         253

______________________________________

          162              |                ?

_______________________________________

91 video games are given to Amany

800

Kate score 193 points in a game. Tom scored 159 points. Which estimate uses rounding numbers to the nearest ten to find how many  more points Kate won than Tom. 

A. 195-100=95

B. 190-160

B

800

590+103

690

900

Sonia wrote a number sentence. What property or properties of addition are used?

24+(5+8)+0=(24+5)+8

Associative and Identity

900

Bob subtracted 334 from 758. How can he check his work using inverse operations?

 758

-544

_____

Add 214 to 544

900

Noor spent $225 for tickets and rides. The cost of tickets is $135. What is the cost of rides?

                               225

______________________________________

        $135                   |               ?

______________________________________

cost of rides is $90 

900
Estimate by rounding to the nearest 10. 75 + 12
What is 90?
900

FIND ACTUAL SUM? 17+24+45

86

1000

Liza wants to find the sum of 85+45+19. What is the way she can find the sum using Associative Property.

85+(45+19)=149

1000

Raya found 540+125=665.How can she check her answer?

Subtract 665-125

1000

Ms. Hashira has 221 coupons. Fayrouz gave her 310 more coupons. Draw a strip diagram to show many coupons does Ms. Hashira now has?

                          ?

___________________________________

221                        |            310 

____________________________________

531 coupons

1000

A summer camp has 376 students. There are 133 students who buy a ticket to zoo and the rest buy a ticket to the museum  which is the most reasonable estimate for how many students buy a ticket to the museum.

A. ABOUT 280

B. About 200

C. ABOUT 300

d. About 250

About 250

1000

There were 67 brown eggs and 59 white eggs. All but only 25 eggs did not hatch. How  many eggs hatched? 

101

1200
This property states that the way in which addends are grouped does not change the sum.
What is the Associative Property of Addition?
1200

Nora found 558-232. His answer was 326. Show how you can check the answer.

 326

+232

 _____

   558

1200

Ali Spent $13 on a cap and a bottle. The cap costs $5. How much does the bottle cost? Draw a strip diagram

                     13

___________________________

  $5                 |           ?

____________ |______________

COST OF THE BOTTLE IS $8

1200

Eva's estimate sum for 204+579 was close to the actual sum. Which estimate could have been Eva's?

A. About 1,000

B. About 700

B

1200

458+982 NEAREST 100

600