Decimal Review

Adding and Subtract Decimals

100

10.357 + 12.062 + 7.506 =

29.925

200

20.000 - 9.925 = 

10.075

300

fifty four and twelve hundredths + seventy six and two tenths 

130.32

400

1.236 + 58.6

59.836

500

2.030 - .058

1.972

Estimate or Round Decimals

100

Estimate by rounding to the nearest tenth 

12.3 + 10.1 = 

about 22

200

Estimate 10.234 + 32.062 by rounding to the nearest tenth

About 42.1

300

Decompose 63.432

             tenths              thousandths

634 tenths 32 thousandths

400

Estimate the answer. 

Rain falls in Seattle 60.15 inches a year

Rain falls in Tacoma 47.63 inches a year

Estimate to the nearest ones place value the number of inches that fall in Seattle and Tacoma. 

60 + 48 = about 108 inches of rain

As a bonus, figure out the exact number of inches it rains a year in Seattle and Tacoma. 

500

Estimate the answer to the following: 

I have 50.7 grams of sugar and I used 38.2 grams. About how many grams do I have left? 

About 51 - 38 = 13 grams 

I would also accept the answer: 

About 12 grams 

Multiply Decimals

100

4.13 x 10³ =

4,130

200

4.6 x 3

13.8

300

15.2 x 4

60.8

400

3.895 x 10³

3,895

500

.987 x 10^{6 =} 

987,000

Divide Decimals

100

413,000 /  10² =

4,130

200

7.13 / 10 =

.713

300

.024 / 6

.004

400

5472 / 10^{3 =}

5.472

500

14.2 / 2

7.1

Comparing decimals

100

2 tenths               11 hundredths 

>

200

13 tenths + 8 tenths + 32 hundredths         2.42 

=

300

342 hundredths                 3 + 49 hundredths 

<

400

2 + .3 + .14               2.324

>

500

.3 x 10² + .007 x 10²             .3 x 10 + .7 x 10² 

<