Units are important even before kids start measuring, because we use units when we count. When we count something, the thing that we’re counting is the unit. We can count trucks, fire trucks, blue trucks, truck wheels, or even all the vehicles, and the unit, the thing we are counting, changes. But this isn’t always clear to children.
In fact, children have a really hard time counting parts of objects, like the number of truck wheels, because they are so focused on the whole object, the number of trucks. [4]Helping children make connections between units and comparisons (based on size, length, amount, etc.) can help them correctly use measurement procedures when they need to. [5, 6] Explicitly labeling the unit when counting is one way to support these connections.
You can support your young child’s early measurement skills by helping make connections between approximation, comparison, counting, and measurement. Here are some tips.
All children are naturally curious about their environment and are constantly comparing things, even before they have the words to describe what they are comparing. You can help your child by using comparison words like bigger, smaller, longer, and taller. For example, My shoes are bigger than your shoes!
As your child starts to use comparison words, you can have conversations about what these comparisons mean and expand on them. For example, when your child says that your shoes are bigger than hers, you could expand by talking about the opposite relation—That’s right! That means your shoes are smaller than mine.—or by being more specific—That’s right! My shoes are longer and wider than yours!
Whenever you count objects or items, you’re measuring! But sometimes it’s hard to see that this process is measurement because the unit, the thing you are counting, isn’t obvious. After counting, label the set and the unit, saying, There are 6 ducks, rather than There are six.
After counting, try counting again, but count a subset. If you just counted all the blocks, now count only the small blocks. This can help children think about why we’re counting. For example, if you want to build a specific structure, do you need to know how many blocks there are in all or just certain kinds of blocks?
After counting, try counting again, but count parts of objects. If you just counted trucks, now count truck wheels. Though counting parts of objects can be confusing, helping children do this builds up their ideas about how the choice of unit affects the total measurement (in this case, what you’re counting). Repeat the unit after counting: There are 3 trucks but there are 12 truck wheels.
Ask your child to help you measure things in different rooms, like windows or lamps, to compare them. How do you do it when you can’t see the objects at the same time? Help your child use a string or even their own body, like arm lengths, to measure the objects and compare them.
Have your child measure the same object with different units. When they measure an object with pennies, then nickels, then quarters, they’ll get different measurements. Ask her to explain why the measurements are different and what happens when she measures using a bigger unit versus a smaller unit.
When your child starts using a ruler, have him use the ruler in different ways. For example, ask your child to measure something that’s not lined up with the end of the ruler, or turn the ruler so the object is lined up with the high end and count down. This helps children think about the purpose of the ruler for showing units and not just for looking at the number where the object ends.
By using the language of measurement and looking for everyday ways to talk about units and measurement, you can help support your child's developing mathematical understanding.