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Fraction Calculators
A fraction calculator is the first tool most people need. Fractions are where maths asks you to hold two numbers as one idea. Most mistakes here are not arithmetic mistakes — they are forgetting what the denominator is for. Every calculator below shows that part.
Every calculator in this branch is checked by a mathematician before it goes live.
- 2⁄3 + 1⁄4 the sum
- 8⁄12 + 3⁄12 rewrite both over the common denominator 12
- 11⁄12 add the numerators, keep the denominator
Calculators
All 15 fractions calculators, by topic
operations first, then the conversions between forms
Operations
Simplifying
Converting
Comparing
Where this sits
What comes before fractions
each topic assumes the one to its left
Stuck part way through? Start at the leftmost topic you are not sure about — everything to the right depends on it.
Knowledge base
Read the reasoning, not just the answer
one article per question a teacher would answer
Questions
Asked often enough to answer here
the ones that change how you work, not trivia
Why do I need a common denominator to add but not to multiply?
Adding means combining parts of the same size, so the parts have to be the same size first — that is what the common denominator does. Multiplying is taking a fraction of a fraction, which does not require matching sizes at all.
Is 0.333… exactly one third?
Yes. The decimal never ends, which makes it look approximate, but the repeating sequence is exactly equal to 1/3. Rounding it to 0.33 is what introduces error.
Should I always simplify my answer?
Unless you are told otherwise, yes. Two thirds and eight twelfths are the same number, but marked work almost always expects the lowest-terms form.
Nearby
Branches that touch this one
linked because the maths overlaps, not because it fills space