Adding 3 numbers
Estimation
Rounding
Do the inverse
Check your work
100

What is the sum of 165, 312, and 289?

766

100

Find a reasonable estimate for the sum of 592 and 339. Select all that apply. a) 690 + 350 = 1040   b)600 + 300 = 900 c) 380 + 450 = 830                   d) 340 + 590 = 930 e) 600 + 340 = 940

b) 600 + 300 = 900

d) 340 + 590 = 930

e) 600 + 340 = 940

100

Round to the nearest ten to estimate the difference of 589 – 471. Enter your answer in the box.

120

100

Which strategy shows a way to check the work using inverse operations for the problem: 345-127 = 218

a) add 127 and 345.      b) add 218 and 345              c) add 218 and 127.      d) subtract 127 from 218

c) add 218 and 127

100

What addition equation can be used to check the answer for 822 – 457 = 365?

365 + 457 = 822

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