Numerical Expressions & Order of Operations

How the lesson starts: Numerical Expressions & Order of Operations

The Secret Code Club
Welcome to the Secret Code Club! Mia's treehouse door has a number lock. The clue says: add 8 and 7, then multiply by 2. To write that as math, we need a special tool: parentheses!
Parentheses go first
Parentheses say: do me first! Add 8 and 7, then multiply by 2, becomes (8 + 7) × 2. Inside first: 8 + 7 = 15. Then 15 × 2 = 30. The code is 30!
Crack 5 × (6 + 4)
What does 5 × (6 + 4) mean? Add 6 + 4 first, because it's in parentheses: 10. Then multiply by 5: 5 × 10 = 50. Watch out: don't do 5 × 6 first and forget the parentheses!