Fractions — Grade 4 Mathematics
In Grade 4, we add and subtract fractions with the same denominator, simplify fractions using common factors, find equivalent fractions, and calculate fractions of whole-number amounts.
Adding and Subtracting Fractions (Same Denominator)
When denominators are the same: add or subtract the numerators only — the denominator stays the same.
38 + 28 = 58 710 − 310 = 410 = 25
38 + 28 = 58 710 − 310 = 410 = 25
³⁄₈
²⁄₈
³⁄₈
Visual: ³⁄₈ + ²⁄₈ = ⁵⁄₈ (orange + dark = 5 out of 8 parts)
Equivalent Fractions
Multiply or divide both numerator and denominator by the same number to make an equivalent fraction.
12
=
24
=
36
=
48
=
510
💡 Simplifying: Divide top and bottom by their HCF. ⁸⁄₁₂ → HCF(8,12)=4 → ²⁄₃.
Fractions of Amounts
To find a fraction of an amount: divide by the denominator, then multiply by the numerator.
Example: ³⁄₄ of 60 = (60 ÷ 4) × 3 = 15 × 3 = 45
Example: ³⁄₄ of 60 = (60 ÷ 4) × 3 = 15 × 3 = 45
Worked Examples
Example 1 — Add and Simplify
Calculate ⁵⁄₁₂ + ³⁄₁₂. Simplify your answer.
- Same denominator → add numerators: 5 + 3 = 8
- Answer: ⁸⁄₁₂
- HCF(8, 12) = 4; divide both by 4: ²⁄₃
Example 2 — Find an Equivalent Fraction
Write ²⁄₅ as an equivalent fraction with denominator 20.
- 5 × 4 = 20, so multiply top and bottom by 4:
- ²⁄₅ = ⁸⁄₂₀
- Check: ⁸⁄₂₀ ÷ ⁴⁄₄ = ²⁄₅ ✓ — ⁸⁄₂₀
Example 3 — Fraction of an Amount 🍕
A pizza shop made 84 pizzas. ⁵⁄₇ were vegetarian. How many vegetarian pizzas?
- ⁵⁄₇ of 84 = (84 ÷ 7) × 5
- 84 ÷ 7 = 12
- 12 × 5 = 60 vegetarian pizzas
Practice Questions
1. Calculate ⁴⁄₉ + ²⁄₉.
✅ 4 + 2 = 6 → ⁶⁄₉ = ²⁄₃ (simplified by dividing by 3)
2. Calculate ⁷⁄₁₀ − ³⁄₁₀.
✅ 7 − 3 = 4 → ⁴⁄₁₀ = ²⁄₅
3. Write ³⁄₄ as an equivalent fraction with denominator 24.
✅ 4 × 6 = 24 → 3 × 6 = 18 → ¹⁸⁄₂₄
4. Find ²⁄₃ of 96.
✅ 96 ÷ 3 = 32; 32 × 2 = 64
5. There are 120 pupils. ⁵⁄₈ study maths. How many is that?
✅ 120 ÷ 8 = 15; 15 × 5 = 75 pupils
Key Points to Remember
- Same denominator? Just add or subtract the numerators.
- Equivalent fractions: multiply or divide top and bottom by the same number.
- To simplify: divide by the Highest Common Factor (HCF).
- Fraction of an amount: ÷ denominator first, then × numerator.
- Always simplify final answers where possible (check for common factors).