📝 Quick Revision + Exam Tips
This post is for:
Quick revision before exams
Clearing confusion
Scoring easy marks
Read slowly. This post is very important 🙂
🔤 1. What are Letter-Numbers?
Letters like a, x, y, n represent numbers
These letters can change value
Expressions using letters are called algebraic expressions
Example:
a + 3
2n
5x + 4y
➕ 2. How to Read an Expression (Exam Friendly)
a + 5 → 5 more than a
a − 4 → 4 less than a
3a → 3 times a
2x + 7 → 7 more than twice x
👉 Always read expressions in words in your mind.
✖️ 3. Multiplication Sign Rule
In algebra:
We do not write ×
We write number first, letter later
Correct:
4n, 7x, 5y
Wrong:
n4, x7
⚠️ 4. Very Common Exam Mistakes (Avoid These!)
❌ 5x ≠ 5 + x
❌ 2(a + b) ≠ 2a + b
❌ x + x ≠ x²
✔ Correct:
x + x = 2x
2(a + b) = 2a + 2b
➕➖ 5. Like and Unlike Terms (High-Scoring Topic)
✔ Like Terms
Same letters:
3a + 5a = 8a
2x − x = x
❌ Unlike Terms
Different letters:
3a + 2b → cannot be added
🧹 6. Steps to Simplify an Expression (Follow This Order)
1️⃣ Open brackets
2️⃣ Change sign if needed
3️⃣ Group same letters
4️⃣ Add or subtract
Example:
(4x + 5y) − (2x + y)
Step by step:
4x + 5y − 2x − y
(4x − 2x) + (5y − y)
2x + 4y
🔍 7. Pattern Questions (Very Important)
If something repeats:
Look for +2, +3, ×2, etc.
Use a letter for step number
Write one formula
Example:
Matchsticks pattern:
2n + 1
Calendar pattern:
Diagonal sums always equal
🧠 8. How to Attempt Word Problems
✔ Read slowly
✔ Decide what letter means
✔ Write expression
✔ Simplify
✔ Substitute value if asked
Never jump to calculation directly.
🏆 9. How to Score Full Marks in This Chapter
✔ Write expressions neatly
✔ Show steps clearly
✔ Use brackets properly
✔ Do not mix unlike terms
✔ Re-check signs (+ / −)
✨ Final Chapter Summary
Algebra = maths with letters
Expressions help explain patterns
Same rules as arithmetic apply
One formula works for many values
If Chapter 4 is clear, future algebra becomes easy.