Dividing a whole number by a unit fraction

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About this video

To find 3 divided by 1/4, the video draws 3 wholes and splits each into fourths. Each whole holds 4 fourths, so 3 wholes hold 3 x 4 = 12 fourths, which means 3 divided by 1/4 = 12.

You'll be able to

  • draw wholes split into fourths to divide a whole number by 1/4.
  • explain why 3 divided by 1/4 = 12.
  • use multiplication to count the pieces quickly.

Key words

unit fraction
A fraction with 1 on top, like 1/4.
fourth
One of 4 equal parts of a whole, written 1/4.
section
One of the equal pieces a whole is cut into.
Transcript

- Lets think about what three divided by one fourth is equal to. Pause this video and see if you can figure it out on your own. And I'll give you a hint, take three wholes and divide it into pieces or sections that are each one fourth of a whole and then think about how many sections you have.

Alright now lets work through this together. Now let me draw three wholes. And so lets say this is... I'm gonna hand draw it, so its not gonna be perfect. But lets say that is one whole right over there. This is two wholes right over there. And then I have my third whole just like that.

And now I'm going to divide it into pieces or sections that are each one fourth of a whole. So this first whole is four pieces that are each one fourth each, of four fourths. And then I have another four fourths right over here. And then I have another four fourths right over here.

Another way to think about it, I took the three wholes, and I divided it into fourths. So if you divide it into fourths how many pieces am I going to have? Well this is pretty straight forward, you have one two three four five six seven eight nine ten 11 12 pieces.

And I didn't even have to count that, each whole is gonna be four fourths. So three wholes is going to be three times four fourths, or 12 pieces or 12 sections. So that is going to be equal to 12. Another way to think about it is if you take three and you divide it into equal sections that are each a fourth you are going to have 12 equal sections.

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