The Number System

Estimating Decimals

100

Estimate 4.5 x 8.3 =

40

200

Estimate 9.8 ➗ 2.9 =

3

300

Estimate 120.3 x 3.9

480

400

Estimate 172.2 ➗ 24.5 =

7 or 9

500

Estimate 651.2 ➗ 78.1 =

8

Multiplying Decimals

100

4.7 x 6 =

28.2

200

38.8 x 4 =

155.2

300

9.8 x 21 =

205.8

400

144.7 x 2.1 =

303.87

500

37.1 x 26.2 = 

972.02

Dividing Decimals

100

3.6 ➗ 12 =

(round answer to tenths place)

0.3

200

57.5 ➗ 5 =

(round answer to tenths place)

11.5

300

3.21 ➗ 1.2 =

(round answer to tenths place)

2.7

400

.0847 ➗ 2.2 =

(round answer to tenths place)

.04

500

1.936 ➗ 5.51 =

(round answer to tenths place)

0.4

Exponents

100

3³ =

27

200

5^{4 =}

625

300

6³ =

216

400

8⁴ =

4,096

500

2¹³ =

8,192

Story Problems

400

Roselyn went to iCandy and bought 22.8 pounds of candy. She divided the candy equally and packed it in boxes. If each box weighed 3.8 pounds, how many boxes did she use in total?

= 6

500

James runs a race at a rate of 6 minutes and 41 seconds per mile. If the race was 2.3 miles long, how long did it take James to finish? Round your answer to the hundredths place.

= 14.74 minutes