The Basics of Decimals Practice Questions

To review writing numbers as decimals, operations with decimals and decimals and fractions, go to The Basics of Decimals Study Guide.

The Basics of Decimals Practice Questions

Problems

Practice 1

Write the following numbers as decimals.

1. 
2. 
3. 
4. 17 hundredths
5. 9 and 6 tenths

Practice 2

1. 34.7 + 4.1 + 0.03 =
2. 125.05 –11.4 =
3. 16.8 × 0.2 =
4. 5.34 × 10 =
5. 42.19 × 0.4 =
6. 1.95 ÷ 0.03 =
7. 245 ÷ 4.9 =

Practice 3

1. Convert to a decimal.
2. Convert 0.12 to a fraction.
3. Which is greatest?

   0.4, 0.07, 0.25, 0.100, 0.009

4. Which is the smallest?

   , 0.5, 0.07, 0.0099, 0.071

5. Change to a decimal.

Solutions

Practice 1

1. 3.2
2. 98.03
3. 23.078
4. 0.17
5. 9.6

Practice 2

1.	Add the numbers vertically; make sure to line up the decimal points and add trailing zeros when necessary:
2.	When subtracting decimals, it is easiest to do the problem vertically, remembering to line up the decimal points.
3.	Multiply without regard to the decimal points: 168 × 2 = 336. Because there are two digits to the right of the decimal points in the factors, move the decimal point two places left in the product: 3.36.
4.	Use the shortcut when multiplying by 10. Move the decimal point one place to the right to get the product of 53.4.
5.	Multiply without regard to the decimal point:
	There are three digits to the right of the decimal points in the factors, namely 1, 9, and 4. Move the decimal point three places to the left: 16.876.
6.	Set up the problem as a long division problem. The divisor (0.03) has two digits to the right of the decimal point, so you must move the decimal point two places to the right in both the divisor and the dividend (1.95). Then, move the decimal place straight up to the quotient to get an answer of 65.
7.	Set up the problem as a long division problem. The divisor (4.9) has one digit to the right of the decimal point, so you must move the decimal place one place to the right in both the divisor and the dividend (245). You must add a trailing zero onto the dividend as a placeholder. Then move the decimal place straight up to the quotient to get 50.

Practice 3

1.	means "seven divided by eight." Divide 7 by 8, using long division, to get 0.875.
2.	0.12 is read as "twelve hundredths." .
3.	Change each decimal to an equivalent decimal—all of which have the same number of digits to the right of the decimal point: 0.4 = 0.400, 0.07 = 0.070, 0.25 = 0.250, 0.100, 0.009. Now 400 > 250 > 100 > 70 > 9; 0.4 is the greatest.
4.	Change all numbers to decimals with four digits to the right of the decimal point: , read as "four tenths." The decimal equivalent of = 0.4000. Also, 0.5 = 0.5000, 0.07 = 0.0700, 0.0099, 0.071 = 0.0710. Now, 5,000 > 4,000 > 710 > 700 > 99; 0.0099 is the smallest.
5.	One of the common fractions that it is helpful to memorize the decimal equivalent of is 0.75. Also, is read as "three divided by four." Divide 3 by 4, using long division, to get 0.75.