01
How to use this calculator
- Count the digits after the decimal point.
- Write the digits over the corresponding power of ten.
- Divide numerator and denominator by their greatest common factor.
02
A little understanding goes a long way.
Every terminating decimal can be expressed exactly as a fraction with a power-of-ten denominator before simplification. 0.333 is 333/1000, whereas 0.333… repeating is 1/3.
THE FORMULA
0.abc = abc / 1000, then simplify
TRY IT ON PAPER
A worked example
0.375 = 375/1000. Dividing the numerator and denominator by 125 gives 3/8.
03
A few common questions
Is 0.333 exactly one third?
No. The finite decimal 0.333 equals 333/1000. Only the infinitely repeating decimal equals one third.
What happens to negative decimals?
The fraction keeps the negative sign. For example, −0.75 = −3/4.