Idea 5of 22Builds on4 × 1/3 is 4 groups of one third
Multiplying is adding the same piece again
Which addition says the same thing as 4 × 1/3?
Today you'll discover
- how × repeats an addition
- how to write 4 × 1/3 as an addition
- why the total is 4/3
Think first4 × 1/3, as pieces laid end to end
Which addition is the same as 4 × 1/3?
Decide first, then press Next. Count the pieces, and count the + signs.
Four tinted pieces of one third laid end to end across bars one whole wide. Under them the line 1/3 + 1/3 + 1/3 + 1/3 = 4/3. The pieces are numbered 1/3, 2/3, 3/3, 4/3, then the sentence 4 × 1/3 = 4/3 = 1 1/3. The last step shows five quarters.
See the whole ideathe big idea and the key word, in one place
The big idea
4 × 1/3 is one third added 4 times: 1/3 + 1/3 + 1/3 + 1/3 = 4/3.
Compare themAdd fractions with the same bottom number by adding the tops: 1/3 + 1/3 = 2/3. The bottom stays 3, because the pieces are still thirds.
Key word
- repeated addition
- adding the same number again and again; 1/3 + 1/3 + 1/3 + 1/3 is 4 × 1/3
Ready to use it?
- Write a product like 5 × 1/4 as an addition.
- Write an addition of one unit fraction as a product.