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Numbers, units and arithmetic
Numbers, units and arithmetic

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3.10 More difficult fraction sums

Sometimes you have to find equivalent factions for all fractions in the sum in order that the denominators are the same.

To add or subtract fractions, use equivalent fractions to make the denominators the same and then add or subtract the numerators.

Example 21

Evaluate .


You cannot change halves to thirds or vice versa, but you can change them both to sixths.

 and . So .