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Equivalent fractions, adding and subtracting
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Fractions describe parts of a whole. To compare, add or subtract them you need the same denominator.
Equivalent fractions
Multiply or divide the top and bottom by the same number.
34 = 68 = 912
To simplify, divide by the highest common factor: 1824 = 34 (÷ 6).
34 = 68 = 912
To simplify, divide by the highest common factor: 1824 = 34 (÷ 6).
Adding and subtracting
Make the denominators the same, then add or subtract the numerators.
23 + 14 = 812 + 312 = 1112
56 − 13 = 56 − 26 = 36 = 12
23 + 14 = 812 + 312 = 1112
56 − 13 = 56 − 26 = 36 = 12
Mixed numbers
A mixed number has a whole part: 212.
As an improper fraction: 212 = 52.
To add, you can turn mixed numbers into improper fractions first.
As an improper fraction: 212 = 52.
To add, you can turn mixed numbers into improper fractions first.
Work out 134 + 212.
- Improper fractions: 74 + 52
- Common denominator: 74 + 104 = 174
- As a mixed number: 414
Answer: 414
Equivalent fractions come from multiplying or dividing top and bottom by the same number. Add or subtract only when the denominators match.
The interactive lesson includes the diagrams for this topic.
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