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Mental Math
Estimate the Sum or Difference
Addition
Subtraction
100
Use metal math (break apart strategy) to solve

430 + 331

761

100

3,438 + 4,987

8,000

100

2,321 + 6,532

8,853

100

6,342 - 4,422

1,920

200

Use metal math (break apart strategy) to solve

6,500 + 813

7,313

200

44,453 - 27,621

10,000

200

6,211 + 9,532

15,743

200

883,688 - 791,447

92,241

300

Use metal math (break apart strategy) to solve

46,900 + 34,018

80,918

300

2,367 + 89 

2,500

300

226,211 + 79,527 =

305,738

300

26,786 - 7,497

19,289

400

Use metal math (break apart strategy) to solve

145,365 + 157,482

302,847

400

48,575 - 34,142

20,000

400

39,522 + 11,758 + 6,826

58,106

400

264,876 - 97,984

166,892