One-Step Equations (+ / −)
📋 What it is
To undo addition or subtraction, do the opposite to BOTH sides to keep the equation balanced.
🗣️ Coach says
An equation is a balance scale — both sides are equal. To get x alone, undo what's done to it using the OPPOSITE, and do it to BOTH sides so it stays balanced. x + 7 = 10 → subtract 7 from both sides.
🧠 Memory hook
Whatever you do to one side, do to the OTHER. Undo with the opposite (+ undoes −).
😂 Giggle
Why did x feel so left out?
Because everyone was always trying to find it, but nobody ever just accepted it for who it was!
😲 Whoa!
The equals sign "=" was invented in 1557 by Robert Recorde, who used two parallel lines because "no two things can be more equal".
✅ Quick check: Solve x + 7 = 10.
Say your answer out loud first — then reveal.
x = 3 — subtract 7 from both sides: 10 − 7 = 3.
Subtraction undoes addition; doing it to both sides keeps the balance.
🧪 Try it! (2 minutes)
Balance a pencil on your finger. Add a coin to one end — you have to move to rebalance. Same idea.