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Commutative/ Associative
Mental Math
Rounding
Word Problems
Mystery
100

What number goes in the blank to demonstrate the Commutative Property?

18 + 2 = ___ = 18

2

100

  1. What should you do to add this equation mentally? 562 + 668
    a. Add 2 to 562 and add 2 to 668
    b. Subtract 2 from 562 and subtract 2 from 668
    c. Subtract 2 from 668 and add 2 to 562
    d. Subtract 2 from 562 and add 2 to 668

d

100

Round 108 to the nearest ten.

110

100

Round each number to the nearest ten. Next, estimate the difference of 739 - 371

769 = 770

341 = 340

770 - 340 = 430

100

What is 555 rounded to the nearest ten? 

560

200

  1. What number goes in the blank to demonstrate the Associative Property? 

         40 + (34 + ____ )   =    (47 + 34) + 40

47

200

  1. What should you do to subtract this equation mentally?  453 - 207                                      a. Add 3 to 207 and add 3 to 453
     b. Subtract 3 from 453 and subtract 3 from 207  c. Subtract 3 from 443 and add 3 to 207
     d. Subtract 3 from 207 and add 3 to 453

c

200

Round 108 to the nearest hundred. 

100

200

What is the sum of 532 and 255 rounded to the nearest hundred?

532 = 800

255 = 300

500 +300 = 800

200

What is 550 rounded to the nearest hundred? 

600

300

What number goes in the blank to demonstrate the Commutative Property?

3456 + 789   =   ____ + 3456

789

300

  1. What should you do to add this equation mentally?                                                                              732 + 888



Subtract 2 from 732 and add 2 to 888

300

Round 165 to the nearest ten. 

170

300

  1. Evan subtracts 247 from 642 and gets 395. 

What addition equation can he use to check his answer? 

______ + ______ = _______

247 + 395 = 642

300

If Mrs. Manochio has 26 pencils in her desk and Ms. D'Achille has 18 pencils in her desk, what it the estimate of how many pencils they have in all to the nearest ten? 

26 = 30

18 = 20

30 + 20 = about 50 pencils 

400

  1. What number goes in the blank to demonstrate the Associative Property? 

      1234 + (789 + ____ )   =    (456 + 1234) + 789

456

400

  1. What should you do to subtract this equation mentally? 403 - 197

Subtract 3 from 403 and add 3 to 197

400

Round 165 to the nearest hundred.

200

400

  1. Felicia earned $173 babysitting in April. She earned $311 in May. 

How much money did she earn in all to the nearest hundred?

173 = 200

311 = 300

300 + 200 = $500

400

Use mental math to solve 316 + 453 by breaking apart the numbers into hundreds, tens, and ones.

300 + 400 = 700

10 + 50 = 60

6 + 3 = 9

700 + 60 + 9 = 769

500

  1. Which equations are true?
    a. 0 + 675 = 0
    b. 130 + 210 = 210 + 130
    c. (127 + 80) + 250 = 127 + (80 + 250)
    d. 497 + 0 = 497

b, c, d

500

Use mental math to solve 513 + 451 by breaking apart the numbers into hundreds, tens, and ones.

500 + 400 = 900

10 + 50 =  60

3 + 1 = 4

900 + 60 + 4 = 964

500

Round 355 to the nearest hundred and ten. 

400 and 360

500

Jen’s HW said to round to the nearest hundred to estimate the sum of 171 and 482.                        

He wrote 170 + 480 = 650. Is Jen correct or incorrect? Why?

Yes Jen is correct because 171 rounded to the nearest hundred is 170 and 482 rounded to the nearest hundred is 480. 170 + 480 = 650. 

500

A  panda in a zoo weighs 164 pounds. It’s sister weighs 238 pounds. What is an estimate of their weight combined to the nearest ten?

164 = 160

238 = 240

160 + 240 = 400 pounds