Dividing unit fractions by whole numbers
- [Instructor] So let's see if we can figure out what 1/3 divided by five is. And I'll give you a hint. Try to draw out 1/3 of a whole and then divide it into five equal sections. Pause this video and try to do that. I always try to work through it together and to help us as I promised or I suggested I guess. We said let's draw 1/3. I will represent a whole by that square right over there. And now let me split up into three equal sections. So this is all hand drawn with the aid of a computer. So it's not going to be perfect. But let's say that that is three equal sections. It's roughly three equal sections. I didn't do it perfectly but you hopefully get the idea. And so 1/3 would be one of those three equal sections. So that's a third right over there that I have just shaded in and I want to divide it into five. I want to divide it by five, I should say. So let's do that. So to divide it by five, I'm gonna divide it into five equal sections. And if I'm dividing that one into five equal sections, let me just divide all of the thirds into five equal sections. I'm essentially just going to make five rows here. One, and I'm gonna eyeball it, so it's going to be approximate. Two, three, and then four and five equal sections. I now split this whole into one, two, three, four, five rows of equal height. Now if I go to my original third and I divide it by five, I would be left with this right over here. But what fraction is this of the whole? Well what I've done now is I've split my whole into 15 equal sections. How do I know that? Well I could count them. One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15. Or you could just say look I had one, two, three thirds and now each of those have been split into one, two, three, four, five equal sections. So three times five is 15. So each of these is a 15th and so the 1/3 divided by five is just one of those 15ths. So that right over there is one of those 15ths. So this is going to be equal to 1/15 and we are done.