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Vocabulary
Estimate
Adding
Subtracting
Word Problems
100

To align decimal points in a decimal addition problem, annex zeros to write _______ so that all addends have the same number of decimal places.

equivalent decimals

100

Estimate by rounding to the nearest whole number.

28.65+10.23

29+10=39

100

3.4+2.6=

3.4+2.6=6.0

100

7.5-2.3=

7.5-2.3=5.2

100

Ed is training for a race. He ran 12.56 miles on one day, 12.98 the second, and 13.04 miles on the third day. How much did he run in all the days?

38.58 miles

200

You can replace the values in a problem with _______ so that it's easier to use mental math to complete the computation. 

Compatible numbers

200

Estimate by rounding to the nearest hundred.

358+293


400+300=700

200

12.75+3.25=

12.75+3.25=16.00

200

$10-$4.75=

$10-$4.75= $5.25

300

When you adjust one number and change another number in the problem to make a computation easier, you use _______.

Compensation

300

Estimate by rounding to the nearest tenth.

15.65-6.45=

15.7-6.5 = 9.2

300

5.08+7.9=

5.08+7.9=12.98

300

15.6-8.49=

15.6-8.49=7.11

400
Because of the __________, I know that 477.75 + (76.89 + 196.25) = (76.89 + 196.25) + 477.75

Commutative Property of Addition

400

Estimate by rounding to the nearest tenth.

14.65-12.15

14.7-12.2= 6.5

400

$4.65+$2.35=

$4.65+$2.35=$7.00

400

12.35-7.8=

12.35-7.8=4.55

500

Because of the ___________, I know that (477.75 + 76.89) + 196.25 = 477.75 + (76.89 + 196.25)

Associative Property of Addition

500

Estimate by rounding to the nearest hundredth.

452.871+763.384

452.87+763.38=1216.25 

500

23.456+7.89=

23.456+7.89=31.346

500

50.007-23.89=

50.007-23.89=26.117