Choosing Appropriate Metric Units of Measurement
When you’re solving mathematical word problems, it is very important to do your best to understand what the problem is trying to tell you. Some problems want you to find the length of an object in a sensible unit. It is a bit weird to measure the height of a person in kilometers. Often, the problem then wants you to answer in meters or centimeters.
It is smart to imagine the situation the problem is describing in your head. This way, you can try to remember similar situations from your own daily life and compare them.
For example, it might be a good idea to imagine something you know the size of. A full carton of milk weighs about one kilogram and can fit one liter. One meter is about the height of your classmates, and your living room has a temperature of about °C. To convert between milli-, centi-, deci- and so on, you either have to multiply or divide by ten, like you learned in prefixes.
Here are a few problems. Think about what you would have answered before you take a look at how we arrive at the correct answer.
Think About This
Which of these can be equal to 2 meters?
Think About This
Which of these could be the weight of an adult person?
What do you think is correct? Here, everything is measured in kilograms, so you cannot remove any of the answers based on this. But remember that one kilogram is about the same as a full carton of milk.
Does an adult person weigh more than 1 carton of milk? More than 7 cartons of milk? More than 70 cartons of milk? More than 700 cartons of milk? How many cartons of milk do you think is closest to the weight of an adult person? The correct answer is 70 kilograms.
