A red car is 411 centimeters long,
a blue car is 500 centimeters long, and a black car is three meters long. Which car is the longest?
In this question, we need to
compare the lengths of three cars. Let’s have a look at the
measurements: 411 centimeters, 500 centimeters, three meters. What do you notice about these
measurements? They’re not all measured in the
same unit, are they? We’ve got two measurements in
centimeters and one in meters. This means that we can’t just
compare the numbers and look at them and see which one is largest.
Instead, we’re going to have to
convert the measurements so that they’re all in the same unit of measurement. Should we change them all into
meters or centimeters? It doesn’t matter which we choose,
but with questions like this, we need to use a bit of common sense. Two of our measurements are already
in centimeters, so the quickest thing to do would be to change the one that’s in
meters into centimeters, and then they’re all in centimeters. We know that one meter is the same
as 100 centimeters, and so three meters is the same as three lots of 100 centimeters
or 300 centimeters.
Now that all our measurements are
in centimeters, we could show them all on a number line. A red car is 411 centimeters. That’s about here on the number
line. A blue car is 500 centimeters
long. And although we said a black car
was three meters, we worked out this was exactly the same as 300 centimeters. We made sure all our measurements
were in the same unit so that we could then compare them. The longest of the three cars is
the blue car.