Fraction calculator
Enter two fractions and choose add, subtract, multiply or divide. Like a teacher, the calculator writes out every step: the common denominator, simplifying and the mixed number.
How it works
Adding and subtracting: use a common denominator
- Change mixed numbers to improper fractions.
- Find the LCM of the denominators and rewrite both fractions with it.
- Add or subtract the numerators and keep the denominator.
- Simplify, and write the answer as a mixed number if needed.
Example: 1⅔ + ¾
- 1⅔ = 5/3
- The LCM of 3 and 4 is 12: 5/3 = 20/12, 3/4 = 9/12
- 20/12 + 9/12 = 29/12
Answer: 29/12 = 2 5/12
Multiplying and dividing
- Multiplying: multiply the numerators, multiply the denominators, then simplify.
- Dividing: dividing by a fraction is the same as multiplying by its reciprocal, for example 2/3 ÷ 4/5 = 2/3 × 5/4 = 10/12 = 5/6.
To learn it properly, read Number and algebra basics: key points, steps and worked examples.
Frequently asked questions
How do I enter a mixed number?
Leave a space between the whole number and the fraction, for example 1 2/3 for one and two thirds. For a negative number put "-" in front, for example -3/4.
Why does the answer need simplifying?
Tests and homework expect fractions in their simplest form. To simplify, divide the numerator and denominator by their highest common factor.
Can I use this for homework?
Use it to check your answers. Work the question out yourself first, then compare each step to find where a mistake happened.