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Key Stage 2MathsFractions

Adding Fractions with Different Denominators — KS2

Adding fractions with different denominators is a Year 5 and 6 objective that requires children to first find a common denominator before adding numerators. This builds on secure knowledge of equivalent fractions and understanding of LCM (lowest common multiple). Our worksheets scaffold the process clearly, helping children develop the three-step method: find the LCM, convert both fractions, then add.

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Key Skills Covered

Common denominators
LCM
Equivalent fractions
Mixed numbers

The Three-Step Method

Step 1: Find the lowest common denominator (the LCM of the two denominators). For example, to add 1/3 + 1/4, the LCM of 3 and 4 is 12. Step 2: Convert both fractions to twelfths: 1/3 = 4/12, 1/4 = 3/12. Step 3: Add the numerators: 4/12 + 3/12 = 7/12. Our worksheets explicitly practice each step separately before combining them.

Adding Mixed Numbers

Year 6 children must also add and subtract mixed numbers (e.g. 2⅓ + 1¾). Our worksheets show two methods: converting to improper fractions first (often easier for complex calculations) and adding whole numbers and fractions separately (useful for simpler cases). Understanding both methods allows children to choose the most efficient approach for each question.

Sample Questions

1

1/3 + 1/4 = ?

Show answer

7/12

2

2/5 + 3/10 = ?

Show answer

7/10

3

3/4 + 2/3 = ?

Show answer

17/12 = 1 5/12

4

2 1/2 + 1 3/4 = ?

Show answer

4 1/4

5

5/6 + 1/4 + 1/3 = ?

Show answer

17/12 = 1 5/12

More Fractions Resources for Key Stage 2

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