Subtracting
Rounding
Estimation: Addition
Estimation: Subtraction
Adding
100

39 - 22 =

17

100
Round 56 to the nearest 10
60
100
Using front-end estimation to the nearest 10: 46 + 72 =
50 + 70 = 120
100
Using front-end estimation to the nearest ten: 65 - 27
70 - 30 = 40
100

26 + 38 = 

64

200

50 - 26 =

24

200
Round 349 to the nearest ten.
350
200

Using front-end estimation to the nearest hundred: 24 + 49 =

20 + 50 = 70

200

Using front-end estimation to the nearest ten: 88 - 59 =

90 - 60 = 30

200

97 + 25 =

122

300

81 - 48 = 

33

300

Round 864 to the nearest hundred.

900

300

Using front-end estimation to the nearest hundred: 120 + 287=

100 + 300 = 400

300

Using front-end estimation to the nearest hundred: 229 - 163

200 - 200 = 0

300

148 + 41 = 

189

400

71 - 26 = 

45

400

Round 743 to the nearest 100.

700

400
Using front-end estimation to the nearest hundred: 423 + 513 + 892 =
400 + 500 + 900 = 1,800
400

Using front-end estimation to the nearest hundred: 523 - 289

500 - 300 = 200

400

138 + 129 =

267

500

140 - 131 = 

9

500

Steven has 555 marbles in his collection. When asked how many he has to the nearest hundred, he should say:__________

600

500

Using front-end estimation to the nearest hundred: 174 + 425 + 212

200 + 400 + 200 = 800

500

Using front-end estimation to the nearest hundred: 875 - 129

800 - 100 = 700

500

202 + 345

547

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