What is the first step in adding or subtracting fractions with different denominators?

Find the least common multiple (LCM) of the denominators.

Explain why it is necessary to find the least common multiple (LCM) when adding or subtracting fractions with different denominators.

The LCM allows you to express the fractions with a common denominator, which is required for performing addition or subtraction.

Grade 8th Grade · Math · 45 min

I can calculate the lowest common multiple to add and subtract fractions with unlike denominators.

Professor Dave Explains · 4:07

Addition and Subtraction of Fractions

3 key concepts

1
When adding fractions with the same denominator, we only add the numerators, not the denominators.
2
To add fractions with different denominators, first find the least common multiple of the denominators.
3
To subtract fractions, find a common denominator, then subtract the numerators.

10 questions · Multiple choice & Short answer

Quick comprehension check

“Solve: ⅖ + ⅔. Show all steps, including finding the least common multiple.”

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