Here are six cards: times 10, times 100, times 1000, divide by 10, divide by 100, divide by 1000. Use a card to complete each calculation.
In each calculation, we start with the number 5.3. Then we have to choose one of the six cards to make each of the calculations correct.
Let’s start with the first calculation. We know we start with 5.3. What do we have to do to this number to give us the answer 0.53? Let’s compare these two numbers. The five in 5.3 is worth five ones, and the five in 0.53 is worth five tenths. The digit five has moved one place to the right, and the number has got 10 times smaller. To make the number 10 times smaller, we would need to divide it by 10.
Now let’s look at the second calculation. What do we need to do to 5.3 to give us an answer of 5300? We know the five in 5.3 is worth five ones. The five in 5300 is worth five thousands. The five digit has moved three places to the left. And we know that five multiplied by 1000 equals 5000. So 5.3 multiplied by 1000 equals 5300. So this is the card we used.
Finally, what do we do to 5.3 to give us an answer of 0.053? We know the five in 5.3 is worth five ones. The five in 0.053 is worth five hundredths. The five digit has moved two places to the right. The number is getting smaller. So we know it’s a division. And we know we’re dividing by 100 because the five digit moved two places to the right, which means it got 100 times smaller.
5.3 divided by 10 equals 0.53, 5.3 times 1000 equals 5300, and 5.3 divided by 100 equals 0.053. We selected the correct card from the six cards to help us complete each calculation.