Multi-step unit conversion examples (metric)

0:00- [Instructor] Tomas dropped off two packages to be shipped. One package weighed 1.38 kilograms, and the other package weighed 720 grams. So the first one they give in kilograms, and the second one they give us in grams. What was the combined weight of both packages in grams?

0:23So what I wanna do is, I'm gonna convert both of these to grams, and then add 'em up to get the combined weight. Well, we already know the second one is 720 grams, but what's the first one in terms of grams? Well, let's see, 1.38, I could write kilograms like that.

0:42Well, if one kilogram is 1,000 grams, and that's what the prefix kilo means, it means 1,000, well, to go from one to 1.38, I'm multiplying by 1.38, so I'm also, if I want it in terms of grams, I'll take 1,000 grams and multiply by 1.38. So this is going to be 1,000 times 1.38 is 1,380 grams, which I could've just denoted with a G, but now let's add those together.

1:14This is the first package, and then the second package is 720 grams, and so if I were to add, this is going to be, let's see, got a zero, 10, well let's see, four plus seven is 11, and then one plus one is two. We get 2,100 grams in total. Let's do another one of these unit conversion examples.

1:45Julia and her friends are making kites out of paper. For each kite, they need a piece of paper that is 0.65 meters wide. How many centimeters, how many centimeters of paper will they need to make four kites? So they tell us how wide the paper is in meters for each kite, but they want the answer in centimeters, and they want it for four kites.

2:12So, let's think about this a little bit. Each kite is 0.65 meters, 0.65 meters. So to go from one to 0.65, you'd multiply by 0.65 on the meters, and so to go to 100 centimeters to the number of centimeters you would need for the width of a kite, you'd similarly multiply by 0.65.

2:38Well, 65 hundredths times 100 is going to be 65, 65 centimeters per kite. So this 0.65 meters wide per kite, in centimeters it is 65 centimeters. Now, they don't want just how much paper will they need to make one kite, they want four kites. So we would multiply this times four.

3:03This is how much we need per kite, so let's multiply that times four. And so let's see, four times five is 20. Four times six is 24, plus two is 26. 260 centimeters of paper for the width of the four kites. Let's do one more of these. This is a volume conversion.

3:26Omar is pouring five liters of water into two goldfish bowls. He spills 200 milliliters of water, and then divides the remaining water evenly between the two bowls. How many milliliters of water does Omar pour into each bowl? So we want our answer at the end in milliliters, and so let's just convert the amount that he starts with into milliliters.

3:51So he starts with five, he starts with five liters. So how many milliliters is that going to be? Well, they tell us one liter is 1,000 milliliters, so if we have five liters, we're multiplying our quantity times five, that's gonna be five times, it's going to be five times as many milliliters, so that's 1,000 times five is 5,000 milliliters, so that's what he starts with.

4:23Now, before he splits this 5,000 milliliters between these two bowls, he spills 200 milliliters, so let's subtract out what he spills, 'cause he, that's not going to be able to be split. Milliliters. And so, that's going to give us, so we're gonna have 4,800 milliliters to split between those two bowls, and so each bowl, that's what they ask us, how many milliliters of water does he pour into each bowl?

4:53Well, see, if he's gonna split this into two bowls, each bowl's gonna get half of this, and so each bowl is going to get half of 4,800, so we just divide that by two, so each bowl is going to get 2,400 milliliters, 2,400 milliliters and 2,400 milliliters. That's how much each bowl is going, that's how much Omar is going to pour into each bowl.