Dividing With Decimals
Dividing a decimal number by a whole number follows the same long-division algorithm as whole-number division, with the decimal point in the quotient placed directly above the decimal point in the dividend. In Grade 6 Saxon Math Course 1, 6.39 ÷ 3 = 2.13 by placing the decimal point above and dividing: 6 ÷ 3 = 2, 3 ÷ 3 = 1, 9 ÷ 3 = 3. When the divisor is also a decimal, multiply both dividend and divisor by the same power of 10 to convert the divisor to a whole number first.
Key Concepts
Property Dividing a decimal number by a whole number is similar to dividing dollars and cents by a whole number. The decimal point in the quotient is directly above the decimal point in the dividend.
Examples $4.2 \div 3 = 1.4$ $4.5 \div 3 = 1.5$ $177.6 \div 8 = 22.2$.
Explanation Think of it like splitting a bill with friends! Just line up the decimal point and divide as you normally would. The most important rule is to keep that decimal point perfectly aligned, right above its spot in the number you're dividing. This keeps the value of your answer correct.
Common Questions
How do you divide a decimal by a whole number?
Set up long division normally. Place the decimal point in the quotient directly above the decimal point in the dividend, then divide as with whole numbers.
Calculate 6.39 ÷ 3.
Place decimal above. 6 ÷ 3 = 2, 3 ÷ 3 = 1, 9 ÷ 3 = 3. Answer: 2.13.
Calculate 4.5 ÷ 5.
4.5 ÷ 5: 4 ÷ 5 = 0 remainder 4, bring down 5 → 45 ÷ 5 = 9. Answer: 0.9.
How do you divide when the divisor is a decimal?
Multiply both dividend and divisor by the same power of 10 to make the divisor a whole number. Then divide normally.
Calculate 0.72 ÷ 0.8.
Multiply both by 10: 7.2 ÷ 8 = 0.9.