# Question Video: Using Scales to Compare the Masses of Two Objects in Grams Mathematics • 3rd Grade

The can of pineapple is ＿ g heavier than the can of corn.

02:45

### Video Transcript

The can of pineapple is what grams heavier than the can of corn.

We’re given two pictures here that can help us find the mass of two different cans of food. We’ve got a can of pineapple and underneath it a can of corn. Now, it might be quite hard to read the dials on these scales. But we can see a magnified version next to them. And we can read these to find out how heavy each can is. Let’s start with the can of pineapple.

Can you see where the needle is pointing? It’s here, isn’t it? Let’s read the scale. It begins at zero. Then we can see 100 grams is labeled, followed by 200 grams, then 300 grams, and 400 grams. We can stop there because we can see that the needle is pointing in between the numbers 300 and 400 on the scale. In fact, it’s halfway between, isn’t it?

Now, do you remember what number is halfway in between 300 and 400? It’s 350. Although we can’t see the number 350 on the scale, we’ve worked out where it is. And so we know that the mass of the can of pineapple is 350 grams. And remember, this question is all about comparing these two masses. So we’re going to have to look at the second scales. It’s the same set of scales, so we can see the numbers 100, 200, 300 grams, and so on. But where’s the needle pointing to this time? We can see that it’s in between the numbers 200 and 300. And halfway in between the numbers 200 and 300 is 250. The mass of the can of corn is 250 grams.

Now that we’ve measured both masses, we can compare them. The can of pineapple is what grams heavier than the can of corn. We know that it’s heavier because 350 is larger than 250. So we know that the can of pineapple weighs more. But how much more? If we look at the ones digit in our numbers, we can see that it doesn’t change if we compare them. And they both contain five tens too, so there’s no change there. But if we compare the hundreds digit, we can see that there’s a difference of one. 350 is 100 more than 250. And so we can say the can of pineapple is 100 grams heavier than the can of corn. The missing number is 100.