Fraction Calculator
Add, subtract, multiply or divide two fractions and get the answer simplified, as a mixed number, a decimal and a percentage, with every step shown.
3/4 + 2/5
23/20
- As a mixed number
- 1 3/20
- As a decimal
- 1.15
- As a percentage
- 115%
3/4 + 2/5 = 23/20, or 1 3/20, which is 1.15 as a decimal.
How it's worked out
- Use a common bottom number
3/4 = 15/20, 2/5 = 8/2015/20 + 8/20 - Add the tops
15 + 823/20 - Simplify
divide top and bottom by 123/20
The four operations
a/b + c/d = (ad + cb)/bd · a/b × c/d = ac/bd · a/b ÷ c/d = ad/bc
Worked example
3/4 + 2/5: the common bottom number is 20, so 15/20 + 8/20 = 23/20. That's 1 3/20 as a mixed number, or 1.15.
Questions people ask
How do I add fractions?
Give them a common bottom number, add the tops, then simplify. 3/4 + 2/5 = 15/20 + 8/20 = 23/20, or 1 3/20.
How do I divide fractions?
Flip the second fraction and multiply. 1/2 ÷ 1/4 = 1/2 × 4/1 = 4/2 = 2.
How do I simplify a fraction?
Divide the top and bottom by their greatest common divisor. 18/24 simplifies to 3/4 by dividing both by 6.
About this calculator
Formula and rules last checked 25 October 2026Written and tested by the CalcPenguin teamReport a problem