Idea 22of 22Builds onHow many people get 1/6 of a pizza?
× or ÷? Read what the story gives you
How do you tell whether a story needs × or ÷?
Today you'll discover
- the one question that picks the operation
- how to write a story as an expression
- how to check the answer makes sense
Think firstTwo ribbon stories with 3 and 1/4
Read the bottom story: 3 m of ribbon, 1/4 m for each bow. Which expression finds the number of bows?
Decide first, then press Next. Find what each story gives you, and what it asks.
Two stories, one above the other. Top: 3 bows, 1/4 m of ribbon each: how much ribbon? Three quarter-metre pieces: 3 × 1/4 = 3/4. Bottom: 3 m of ribbon, 1/4 m for each bow: how many bows? Three bars cut into quarters numbered 1 to 12: 3 ÷ 1/4 = 12. The last step shows two baking stories.
See the whole ideathe big idea and the key word, in one place
The big idea
Given the number of groups, multiply. Given the amount, divide to count the groups.
Story to expression“5 cups, each 1/2 full”: groups given, 5 × 1/2. “5 cups of juice, 1/2 cup a glass”: amount given, 5 ÷ 1/2.
Easy to get wrongBoth stories use the same numbers. Do not choose by the numbers; choose by what is given and what is asked.
Key word
- word problem
- a story with numbers in it that asks a question for you to answer
Ready to use it?
- Write a story about unit fractions as × or ÷, then solve it.