Beginner · 10 min
Adding unlike fractions
Use a common denominator to add and subtract fractions.
Make equal-sized parts
Fractions need the same denominator before you add them. Multiply both parts of each fraction by the same number to keep its value.
Worked example
1/2 + 1/3 = 3/6 + 2/6 = 5/6
Subtract and simplify
Once denominators match, subtract the numerators. Simplify by dividing the numerator and denominator by a common factor.
Worked example
5/6 − 1/3 = 5/6 − 2/6 = 3/6 = 1/2
Measure a mixture
- Find the total of 1/3 litre and 1/4 litre.
- Draw equal-sized parts to show why adding the denominators would give the wrong result.