Last updated: October 22, 2026 · Written by the Math Made Easy math teachers
Looking for 6th grade decimal operations? Then this Grade 6 lesson on Decimal Operations: Add, Subtract, Multiply, Divide explains each idea step by step, with worked examples.
Quick answer: To add or subtract decimals, line up the decimal points. To multiply, ignore the points, multiply, then give the product as many decimal places as both factors have. To divide by a decimal, multiply both numbers by a power of 10 so the divisor is whole.
Standards: 6.NS.B.3 · Level: Grade 6
How do you add and subtract decimals?
- Line up the decimal points, one under the other.
- Fill empty places with zeros.
- Add or subtract as with whole numbers.
- Bring the decimal point straight down into the answer.
Find 14.7 + 3.85. Write 14.70 and 3.85 in columns: the hundredths give 0 + 5 = 5, the tenths 7 + 8 = 15, and so on.
Answer: 18.55.
How do you multiply decimals?
Multiply as if there were no decimal points, then give the product as many decimal places as the two factors have together.
For 2.4 × 1.5, 24 × 15 = 360. The factors have 1 + 1 = 2 decimal places, so the product is 3.60 = 3.6.
How do you divide decimals?
When the divisor is a decimal, multiply the divisor and the dividend by the same power of 10 so the divisor becomes a whole number. Then divide as usual and keep the decimal point above the one in the dividend.
For 7.14 ÷ 0.6, multiply both by 10 to get 71.4 ÷ 6 = 11.9. If a division does not end, add zeros after the decimal point and keep dividing.
How do you check where the decimal point goes?
| Operation | Rule | Example |
|---|---|---|
| Add or subtract | align the points | 20 − 7.35 = 12.65 |
| Multiply | count places in both factors | 0.08 × 0.9 = 0.072 |
| Divide | make the divisor whole | 0.96 ÷ 0.08 = 12 |
Estimate with rounded numbers: 2.4 × 1.5 is about 2 × 1.5 = 3, so 3.6 is reasonable and 36 or 0.36 is not.
Lining up the last digits instead of the decimal points. In 3.7 + 12.45, the 7 is in the tenths place and must sit above the 4.
Use money to check decimals: $0.25 times 4 is $1.00, so 0.25 × 4 = 1. If your answer would not make sense as dollars and cents, look again.
- Add and subtract by aligning decimal points and filling zeros.
- Multiply as whole numbers, then count the decimal places in both factors.
- To divide by a decimal, make the divisor a whole number first.
- Estimate to check where the decimal point belongs.
- Money problems are a quick reasonableness check.
Decimal Operations: Add, Subtract, Multiply, Divide: frequently asked questions
How do you add decimals?
Line up the decimal points, fill empty places with zeros, and add as with whole numbers. Bring the decimal point straight down into the sum.
How do you know where to put the decimal point when multiplying?
Count the decimal places in both factors and give the product that many places. For 2.4 × 1.5 there are two, so 360 becomes 3.60.
How do you divide by a decimal?
Multiply the divisor and the dividend by the same power of 10 until the divisor is a whole number. Then divide normally, so 7.14 ÷ 0.6 becomes 71.4 ÷ 6.
What if a decimal division does not come out even?
Add zeros after the decimal point in the dividend and keep dividing. For example, 7 ÷ 8 becomes 7.000 ÷ 8 = 0.875.
How can estimating help with decimals?
Round each number to a friendly value and compute. Since 2.4 × 1.5 is close to 2 × 1.5 = 3, an answer of 3.6 is reasonable but 36 is not.