⚖️ Equation

The equals sign means “balanced”

= means both sides have the same value, like a see-saw that is level. It does not just mean “the answer comes next”.

10 + 5 = ? + 7 → the left side is 15, so ? + 7 must make 15 → ? = 8

Use the opposite (inverse) to find the missing number

• ? + 8 = 15 → 15 − 8 = 7
• ? × 6 = 42 → 42 ÷ 6 = 7
• n − 4 = 9 → 9 + 4 = 13 (a letter works just like a box)

Two steps? Undo them backwards

2 × n + 3 = 17

1. Undo the + 3 first: 17 − 3 = 14
2. Then undo the × 2: 14 ÷ 2 = 7
3. Check: 2 × 7 + 3 = 17 ✔

Watch out! In 20 − ? = 12, the answer is 8, not 32. Ask yourself: 20 take away what leaves 12?

Top tip: always put your answer back into the equation to check that both sides match.