Operations and Algebraic Thinking: Using Parentheses, Brackets, and Braces in Expressions (CCSS.5.OA.1)

Brackets first: $9 - 4 = 5$. Then multiply: $5 \times 3 = 15$. Mistake to avoid: $9 - (4 \times 3) = -3$ (doing multiplication before the brackets).

Do the parentheses first: $3 + 2 = 5$. Then multiply: $5 \times 4 = 20$. Common mistake: ignoring parentheses gives $3 + (2 \times 4) = 11$.

Parentheses first: $2 + 1 = 3$. Then multiply: $3 \times 3 = 9$. Last, add: $6 + 9 = 15$. Common mistakes: $(6 + 3) \times 3 = 27$ or $6 + 3 \times 2 + 1 = 13$.

Parentheses first: $2 + 2 = 4$. Then divide: $8 \div 4 = 2$. Common mistake: $8 \div 2 + 2 = 6$ (ignoring the parentheses).