Quick answer
Enter two fractions in simple or mixed form. The tool converts mixed values to improper fractions, finds a common denominator, adds, reduces, and shows both improper and mixed results when applicable.
Formula
- Simple: numerator and denominator per fraction
- Mixed: whole + n/d → (W×d+n)/d
- Output: reduced sum + work line
Introduction
Calculators are for speed and checking, not replacing the reason you need a common denominator. This tool shows enough of the middle work that you can compare it to your notebook.
Everything runs locally. Numerators and denominators are not uploaded to a server, which matters on shared school devices and privacy-conscious workflows.
For ready-made numerators and denominators to type in, open the adding fractions examples page and copy one sum at a time.
What the tool does
Simple form expects one numerator and one denominator per fraction. That covers proper fractions and improper fractions without a separate whole field.
Mixed form adds a whole number field W. Leave W blank or 0 when you only need a proper fraction. The tool builds (W×d + n)/d before it searches for a common denominator.
If you are learning the steps for the first time, pair each entry with the how to add fractions sequence so you know why the work line looks the way it does.
Logic behind the scenes
- lcm for common denominator
- Scale numerators
- gcd reduction on the sum
The implementation follows standard arithmetic: improper conversion, LCD, addition, simplification. That is the same path described in textbooks, which makes the tool useful for homework verification.
If a denominator is zero, the tool blocks the result because division by zero is undefined. Inputs are whole numbers, which matches most classroom worksheets.
How to use the calculator
- Choose Simple or Mixed form Use the switcher above the fraction fields. Mixed is for values like 2 3/4.
- Enter both fractions completely Results update as you type valid numerators and denominators. Both fractions need nonzero denominators.
- Read the sum and work line Check the reduced improper answer, the mixed form if shown, and the scaling step for your teacher’s required work format.
Example: 1/4 + 2/3 in the tool
Enter 1 and 4 for the first fraction, 2 and 3 for the second. The LCD is 12.
You should see scaling to 3/12 + 8/12 and a final sum of 11/12.
Try a mixed example next: 1 1/2 + 2 1/4 in Mixed form should yield 3 3/4 after improper conversion and addition.