Tuesday
Tuesday: Fraction times a whole number
Donnie kneels beside four tiny seedlings in the soft spring soil.
"Each seedling needs 2/3 of a cup of water," he says quietly.
"How much water do all four need?"
Bennie counts the seedlings. "That is 4 groups of 2/3, so we multiply," he says.
Then Donnie notices 12 acorns under the oak tree.
"The squirrels may take 2/3 of them," he says. "How many is that?"
Bennie nods. "2/3 of 12 is also a multiplication."
Learn it: groups of a fraction
4 × 2/3 means 4 groups of 2/3.
2/3 + 2/3 + 2/3 + 2/3 = 8/3.
A quick way: multiply the numerator by the whole number. 4 × 2 = 8, so 4 × 2/3 = 8/3.
8/3 is 2 2/3 cups of water.
Learn it: a fraction of a group
2/3 of 12 means 2/3 × 12.
Split 12 acorns into 3 equal groups of 4. Two of those groups make 8.
So 2/3 × 12 = 8. Another way: 2 × 12 ÷ 3 = 24 ÷ 3 = 8.
- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
- Think about the quick way.
- Tap the steps in order.
| Sentence | True or false? |
|---|---|
| 4 × 2/3 = 8/3 | ? |
| 3 × 2/5 = 6/15 | ? |
| 2/3 × 12 = 8 | ? |
| 3/4 × 8 = 6 | ? |
Split them into 3 equal groups.
Push 2 of the groups together. That is 2/3 of 12.
Now try 3/4 of 12 by making 4 equal groups.
Great work! Tomorrow we multiply a fraction by a fraction.