Writing Number Sentences Created by Mr. Hemmert

ARMT 9 Write number sentences for word problems that involve multiplication or division.

Getting the Idea You can often write a number sentence to solve a word problem. A number sentence uses numbers, operation symbols ( +, -, ×, ÷), and an equal sign (=) to represent a mathematical situation.

Example 1 Mrs. Sheppard bought 16 books. Each book cost $5. Which number sentence could be used to find the total cost of the books? a.$ = b.$16 – 5 = c.$16 × 5 = d.$16 ÷ 5 = e.Answer: C

Example 1 Explained Mrs. Sheppard bought 16 books. Each book cost $5. Which number sentence could be used to find the total cost of the books? Choose the Correct Operation: –Step 1: Look for key words in the problem. The key word “total” means you should either add or multiply. –Step 2: Decide if you should add or multiply. Think: 16 books that cost $5. That’s like 16 groups of $5 bills. The easiest way to solve the problem is to multiply $16 × 5

Example 2 Steve read that 128 players entered the basketball tournament in his town. The organizers split the players into 16 teams, with an equal number of players on each team. What number sentence can be used to determine P, the number of players on each team?

Example 2 Explained Steve read that 128 players entered the basketball tournament in his town. The organizers split the players into 16 teams, with an equal number of players on each team. What number sentence can be used to determine P, the number of players on each team? Strategy –Step 1: Look for key words in the problem. The key words “split” and “equal numbers of players on each team” mean you should divide. –Step 2: What numbers do you divide? Think: 128 players split into 16 equal teams. You need to divide 128 by 16. –Step 3: Write the number sentence The problem says to use the variable P to represent the number of players on each team. –168 ÷ 16 = P

Example 3 Kyle has 350 paperclips. He will put the same number of paperclips into 5 boxes. Which number sentence could be used to determine the number of paperclips Kyle will put in each box? a.350 × 5 = b.350 ÷ 5 = c = d.350 – 5 =