Two-Step Equations

How the lesson starts: Two-Step Equations

Jojo's card club
Hi there! Jojo collects dragon trading cards. She bought 4 packs with the same number of cards in each. Her friend Sam gave her 3 extra cards. Now she has 19 cards. How many cards were in each pack?
Write the equation
Let's turn the story into math. Each pack has x cards, so 4 packs is 4x. Add the 3 extra cards: 4x + 3. That equals 19 cards. The equation is 4x + 3 = 19. Packs times x, plus the extras, equals the total.
Worked example: solve it
Think of a balance. Step 1: undo the + 3 by subtracting 3 from both sides. 19 − 3 = 16, so 4x = 16. Step 2: undo the × 4 by dividing both sides by 4. 16 ÷ 4 = 4, so x = 4. Check: 4 × 4 + 3 = 19. It balances!