🔤 Algebra Basics (Variables & Equations)
Last Updated: 06-Sep-2025
Algebra is math with letters and symbols.
We use letters (like x, y, z) to represent unknown values.
👉 Example:
- "I have some chocolates. If I add 5 more, I get 12."
- Algebra form: x + 5 = 12
- Here, x = unknown number of chocolates.
Variables
A variable is a symbol (usually a letter) that stands for a number.
- Example: x = 10, y = 5
👉 Real life:
- Taxi fare = ₹50 + ₹10 x kilometers
- If km = 5 → fare = 50 + 10x5 = 100
Simple Equations
An equation shows that two things are equal.
👉 Example:
- x + 3 = 7
- To solve: subtract 3 from both sides → x = 4
Steps to Solve
- Keep variable on one side.
- Do same operation on both sides.
- Simplify to find value.
Examples
- Age Puzzle
- Rahul is 5 years older than his sister.
- If Rahul is 12, find sister's age.
- Equation: Sister = x → x + 5 = 12 → x = 7.
- Shopping
- 2 pens cost ₹20.
- Cost of 1 pen = 20 ÷ 2 = 10.
- Equation: 2x = 20 → x = 10.
Quick Practice
- Solve: x + 7 = 15
- Solve: 2x = 18
- A number minus 5 is equal to 9. Find the number.
- A rectangle has length = x and width = 4. If perimeter = 18, find x.
