Idea 17of 22Builds onOne egg is 1/6 of a carton
× and ÷ undo each other
If 12 × 1/3 = 4, what is 4 ÷ 1/3?
Today you'll discover
- how a × fact gives a ÷ fact
- why 12 thirds make 4 and 4 holds 12 thirds
- how to check a division
Think first12 × 1/3 = 4
12 × 1/3 = 4. So how many thirds fit in 4 wholes?
Decide first, then press Next. Read the same picture as × and then as ÷.
Twelve tinted pieces, each 1/3, slide together into 4 bars, each marked = 1 whole, and are counted 1/3 to 12/3. Underneath: 12 × 1/3 = 12/3 = 4, and so 4 ÷ 1/3 = 12. The last step shows 8 quarters filling 2 wholes.
See the whole ideathe big idea and the key word, in one place
The big idea
Multiplying and dividing undo each other: 12 × 1/3 = 4, so 4 ÷ 1/3 = 12.
Like whole numbers3 × 4 = 12, so 12 ÷ 4 = 3. In the same way, 12 × 1/3 = 4, so 4 ÷ 1/3 = 12.
Key word
- inverse operations
- two operations that undo each other, like × and ÷
Ready to use it?
- Write the division fact that goes with a multiplication by a unit fraction.