Base 10
2 x 2
3 x 2
3 x 3
Estimation
100

12 x 10

120

100

12 x 21

252

100

321 x 24

7,704

100

253 x 124

31,372

100

Estimate the following: 22 x 4

20 x 4 = 80 

therefore 

22 x 4 ≈ 80

200

12 x 100

1,200

200

32 x 41

1,312

200

167 x 35

5,845

200

122 x 103

12,566

200

Estimate the following 32 x 6

30 x 6 = 180

therefore

32 x 6 ≈  180

300

200 x 20

4,000

300

48 x 25

1,200

300

408 x 29

11,832

300

345 x 124

42,780

300

Estimate the following: 48 x 4

50 x 4 = 200

therefore

48 x 4 ≈ 200

400

200 x 400

80,000

400

59 x 12

708

400

924 x 65

60,060

400

650 x 402

261,300

400

Estimate the following: 102 x 3

100 x 3 = 300

therefore 

100 x 3 ≈ 300

500

350 x 1000

350,000

500

98 x 35

3,430

500

192 x 43

8,256

500

682 x 902

615,164

500

Estimate the following: 198 x 2

200 x 2 = 400

therefore

198 x 2 ≈ 400