Fraction division in context

- [Instructor] We're told that a group of three friends is practicing for the track meet. The group is going to run 1/2 of a mile total. If they each run the same distance, how far will each person run? Which expression could represent this situation? So pause this video and try to figure this out on your own. All right, the way I think about it is there's some distance that they're going to try to travel. So in this case, it's half of a mile and they're going to divide that distance amongst the three friends. And so the distance that each of them are going to run is the total distance divided by the number of folks that are running. So an expression that represents this is 1/2, the total distance they're running, divided by the number of people who are going to split that distance, divided by three. And so that is choice C right over here. Now it might have confused you a little because you're not used to dividing a smaller number, especially a fraction, by a lager number but that's exactly what's going on over here. You're taking the total distance and it's being split amongst three friends. So the total distance divided by three friends will tell you how far each of them has to run. Let's do another example. So here, we are, actually they're telling us that there's some problem that can be solved with 1/2 divided by seven. They say which problem can we solve with 1/2 divided by seven? And then they give us three different scenarios that we could try to solve. So pause this video and think of which of these three scenarios can be solved with this expression. All right, let's go through each of the choices. Cara ordered seven pizzas for her birthday party. Her parents ate 1/2 of a pizza before the party. How much pizza is left for the party? All right, so what's going on here? She started with seven pizzas, she starts with seven. Her parents ate 1/2 of a pizza. So 1/2 of a pizza is taken away. And so that would tell you how much is left. So this is definitely, this is the expression you would solve to figure out A, not this expression up here. So I would rule this out. Walt has seven hamsters. Each hamster weighs 1/2 of a kilogram. What is the total weight of the hamsters? Well to figure out the total weight, you would start with the number of hamsters and you would multiply that times the weight of each hamster. So that would be seven times 1/2, so we could rule that one out. So it's likely going to be C but let's figure this, let's make sure it makes sense. Jenae has 1/2 kilogram of trail mix. She splits her trail mix evenly between seven friends. How much trail mix will each friend get? All right, she has a total amount, 1/2 of a kilogram and she's going to divide that total amount, she splits her trail mix evenly between seven friends so she's going to take this 1/2 and split it evenly amongst seven friends to get a certain amount per friend. How much trail mix will each friend get? And that's exactly what that expression up there is so I am liking this choice.