How to convert a decimal to a fraction
- Type the decimal, such as 0.375 or 2.25.
- For a repeating decimal, put the repeating digits in brackets: 0.(3) is 0.333…, and 0.1(6) is 0.1666….
- Read the fraction in simplest form, the mixed number and the percent.
Why simplest form
Every decimal with a finite number of digits is a fraction over a power of ten, and dividing the top and bottom by their greatest common factor gives the simplest form. 0.5 is 5/10 = 1/2, and 0.125 is 125/1000 = 1/8. Simplest form is what teachers expect and what rulers and recipes use.
Repeating decimals are fractions too
A decimal that repeats forever is still an exact fraction, which is why 0.999… equals 1: it’s 9/9. Calculators can only show a rounded version of these, so typing the repeating part in brackets gives the exact answer rather than an approximation of a rounded number.