Adding fractions with unlike denominators means expressing each fraction in an equivalent form with a common denominator so the addends represent equal-sized parts, then adding the numerators while preserving that unit and simplifying the result. This includes proper fractions and mixed numbers with whole-number denominators, including conversion between mixed and improper forms when useful; adding denominators directly and working with algebraic rational expressions are beyond this scope.
To add fractions with unlike denominators, first rewrite them with the same denominator. Then add the numerators and keep the common denominator.
Example: Find
Find a common denominator.
Multiples of include .
Multiples of include .
The least common denominator is .
Rewrite each fraction with denominator .
Add the numerators and keep the denominator.
So,
Remember: Do not add the denominators. Once the denominators match, add only the numerators.
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