Multiplying Decimals
Multiplying decimals is the same as multiplying two whole numbers. You just need to remember the following:
- If there is one digit after the decimal point in the question, there will be one digit after the decimal point in the answer.
- If there are two digits after the decimal point in the question, there will be two digits after the decimal point in the answer etc.
For example to calculate 7.12 × 2 we work out 712 × 2 and then work out where to put the decimal point.
712
× 2
____
1424
There are two digits after the decimal point in the question (7.12 x 2), so there will be two digits after the decimal point in the answer. Therefore 7.12 × 2 = 14.24
This video shows you how to multiply decimals.
Dividing Decimals
When dividing a decimal by a whole number, divide as usual but keep the decimal points aligned as in above.
If you are dividing a decimal by another decimal, you need to use equivalent fractions.
For example, 6.12 ÷ 0.2 means 6.12 / 0.2 which is the same as 61.2 / 2 (we have multiplied the numerator and denominator by 10).
Remember to always multiply the numerator and denominator by the same number. And make sure that the denominator is a whole number.
This video shows you how to divide decimals
