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Estimation
Rounding
Addition
Subtraction
Multiplication
100

Estimate the difference.

87 - 28 =

60

100

Round to the nearest ten. 

81

80

100

Solve using Count On.

341 + 204 = 

545

100

Solve using Count Back.

576 - 342 =

234

100

Solve using Repeated Addition.

2 x 6 =

12

200

Estimate the sum.

233 + 498 =

700

200

Round to the nearest ten.

138

140

200

Solve using Adjusting. 

112 + 98 =

210

200

Solve using Think Addition. 

578 - 196 =

382

200

Solve using Equal Groups.

5 x 2 =

10

300

Estimate the sum.

457 + 113 = 

600

300

Round to the nearest hundred.

652

700

300

Solve using Partial Sums.

543 + 389 = 

932

300

Solve

857 - 324 =

533

300

Solve using Number Line.

7 x 3 =

21

400

Estimate the difference.

772 - 431 =

400

400

Round to the nearest ten.

889

890

400

Solve using Partial Sums.

477 + 296 = 

773

400

Solve using Count Back.

658 - 562 =

96

400

Show an Array for

5 groups of 3

15

500

Estimate the sum. 

375 + 289 + 151 =

900

500

Round to the nearest hundred.

909

900

500

Solve using Count On.

305 + 244 =

649

500

Solve

783 - 551 = 

232

500

Solve using Number Line.

7 x 4 =

28