Dividing decimals
Shift the point and make it easy
What is this about?
Dividing by a number with a decimal point looks hard, but there's a trick that turns it into an ordinary division. The idea is to get rid of the point in the divisor before you start.
The rule to remember
Shift the divisor's point to the right until it's a whole number, and shift the dividend's point exactly the same number of places. Then divide normally. It works because multiplying both numbers by 10 or 100 doesn't change the result of a division.
Example 1
4.5 ÷ 0.3
- 1Look at the divisor, 0.3: it has 1 decimal.
- 2Shift its point 1 place to the right and it becomes 3.
- 3Do the same to the dividend: 4.5 becomes 45.
- 4Now divide normally: 45 ÷ 3 = 15.
Result: 15
Example 2
6.25 ÷ 0.25
- 1The divisor 0.25 has 2 decimals.
- 2Shift the point 2 places: 0.25 becomes 25.
- 3Shift 2 places in the dividend too: 6.25 becomes 625.
- 4Divide: 625 ÷ 25 = 25.
Result: 25
The most common mistake
Many people write
Shifting the point only in the divisor
Why it's wrong
If you move the point in one number but not the other, you've changed the division into a different one. You must move it the same number of places in both, always.
Did it click?
The best way to find out is to try. These exercises are exactly on this topic.
Practise this topic