Algebraic identities — Maths worksheet

The method

Split into easy parts — “write a hard number as a round number plus or minus a small one”

1. (a + b)² = a² + 2ab + b².
2. (a − b)² = a² − 2ab + b².
3. (a + b)(a − b) = a² − b²; so a² − b² = (a + b)(a − b).
4. a² + b² = (a + b)² − 2ab = (a − b)² + 2ab.

Use it for: Quick multiplication in your head, checking long multiplication, and the algebraic expressions and identities chapter of Class 8 maths.

Worked example: Use (a + b)(a − b) = a² − b² to find 53 × 47. → 2491

✏️ Practice

Work it out in your head or on paper, then tap your answer — or type it and press Check. Stuck? Press “Show me how”.

🏁 Lesson 61 test

20 sums. Check each answer, then go to the next one. Get 16 or more right to pass.

🏅 Sign in with Google to earn the 🪄 Identity Wizard badge when you pass — and a certificate when you finish all 8 lessons of Part 8 · Class 8. You can still take the test without signing in.

🖨️ Class 8 Maths Worksheet: Algebraic Identities

• Worksheet set 1 (PDF)
• Worksheet set 2 (PDF)
• Worksheet set 3 (PDF)