Natalie has 25.9 metres of cloth. If she wants to make shirts and each one needs 1.95 metres, about how many shirts can she make?
We know that Natalie has 25.9 metres of cloth. And for every shirt, she will need 1.95 metres. So to calculate how many shirts she could make, we would have to divide 25.9 by 1.95. But there’s a very important word in the question. We’re not asked to find the exact amount of shirts that Natalie could make. We’re asked “about” how many shirts can she make. This tells us that we need to estimate the answer.
To help us estimate, the first thing we need to do is round 25.9 to the nearest whole number. 25.9 is between the numbers 25 and 26. And we can see from our number line that the nearest whole number is 26. 1.95 is between one and two on the number line. And we can see the nearest whole number is number two. So 1.95 rounded to the nearest whole number is two.
Now we have an easier calculation to work with. 26 metres divided by two metres. Dividing by two is the same as halfing a number. Half of 26 is 13. If Natalie has 25.9 metres of cloth and each shirt needs 1.95 metres, she will be able to make about 13 shirts. We rounded 25.9 to 26, and we rounded 1.95 to two. And 26 divided by two equals 13. Natalie can make about 13 shirts.