Video Transcript
Is 4.99 metric tons equal to 4990000 grams?
This is an example of what we call a closed question. The answer isn’t going to be a number. It’s either going to be yes or no. So it might seem like quite a simple question. We’ve only got two choices. But we need to base our decision on maths. And we need to think carefully about the facts that we already know that can help us.
The question mentions two measurements. These are measurements of mass. We have 4.99 metric tons. And then, we also have 4990000 grams. Notice how these two units of measurement are different. To start with, we need to think about how many grams there are in a one metric ton. And then, we’ll use this fact to help. The first fact we know that will help us is that 1000 grams are the same as one kilogram. This is quite a common fact.
The next fact is not so well known. 1000 kilograms are the same as one metric ton. So if 1000 grams are the same as one kilogram and 1000 kilograms equal one metric ton, then one metric ton is the same as 1000 times 1000 grams. And a thousand thousands are one million. A thousand thousands are the same as one million. And so, one metric ton is the same as one million grams. We can use this fact now to help us solve the problem. Because there are one million grams in one metric ton, to convert metric tons into grams, we need to multiply by one million. Multiplying by a million is the same sort of idea as multiplying by a 10, 100, 1000, and so on. It involves the digit shifting to the left.
Here’s the number of metric tons that we have: 4.99. Now, we may know how to multiply this number by 1000. We shift the digits three places to the left when we multiply by 1000. We’ve already said that one million is one thousand thousands. So instead of shifting these digits three places to the left, we need to shift them six places to the left. A good way of remembering this is that one million has six zeros. This gives us a clue as to how many times to shift those digits. Let’s move them six times. One, two, three. Now, we need to start putting zeros in as placeholders to show that we’re shifting the digits. Four, five, six. Let’s read the number of grams that are equal to 4.99 metric tons: 4990000. This is exactly the same as the measurement in the question. The two measurements are equal.
So although this problem seemed like a simple yes/no question, we still had to work out the maths behind it in order for us to come to an answer. Is 4.99 metric tons equal to 4990000 grams? Yes, it is.
