Converting decimals to fractions
In a nutshell
Decimals and fractions are often used alongside each other and it's important to be able to convert between the two - with and without a calculator.
Decimals to fractions
Procedure
1.
| Identify the place value of the last digit.
|
2.
| Write all the digits of the decimal as the numerator.
|
3.
| Choose the denominator based on the place value column of that last digit: - For tenths: 10.
- For hundredths: 100.
- For thousandths: 1000.
|
4. | Simplify the fraction if required.
|
Example 1
Write 0.24 as a fraction in its simplest form.
Identify the place value of the 4.
4 is in the hundredths column.
Write 24 as the numerator and 100 as the denominator.
0.24=10024
Simplify by dividing the top and bottom by four.
100÷424÷4=256
Fractions to decimals
With a calculator
To convert a fraction to a decimal using a calculator, simply divide the numerator by the denominator.
Example 2
Write 3215 as a decimal.
Type in 15÷32 on a calculator and write down the answer.
15÷32=0.46875
Without a calculator
Procedure
1.
| Use equivalent fractions to get either 10,100 or 1000 as the denominator. |
2.
| Convert using the following rules:
DENOMINATOR
| RULE
| 10
| Place the ones digit of the numerator in the tenths column and place every other digit in order to the left.
| 100
| Place the ones digit of the numerator in the hundredths column and place every other digit in order to the left.
| 1000
| Place the ones digit of the numerator in the thousandths column and place every other digit in order to the left.
|
|
Note: Remember if the fraction is equivalent to 41,21 or 43, it can be converted to 0.25,0.5 or 0.75.
Example 3
Write 153 as a decimal.
Divide top and bottom by three.
15÷33÷3=51
Multiply top and bottom by two.
5×21×2=102
Place the two in the tenths column and fill in the ones column with a zero.
153=0.2