Why kids struggle with estimating quantities

Kids aren’t born knowing how to estimate. It’s a skill that needs to be taught. It involves: 

Understanding quantity. Babies are born with a basic sense of quantity. Young kids can typically sense when some quantity is more than another, but they don’t automatically know how to say it in words.

Representing quantities. Kids need to match a number word to a quantity, like saying “five” to represent five dots. They also need to know that the numeral 5 is the same as the word five, and that both represent a group of five objects.

Understanding that quantities don’t have to be fixed. Kids need to grasp the idea that “around 10 dots” might be more or less than exactly 10.

Counting and calculating. Kids’ ability to estimate improves as they get better at counting and calculating exact numbers. For example, knowing that 20 + 20 = 40 makes it a lot easier to estimate what 23 + 25 is.

Learn more about number sense skills.

When kids have trouble with estimating, you might see them:

• Give estimates that are wildly off

• Change their estimate if an object is bigger in size — for example, estimating that a group of five large apples is more than a group of eight small apples

• Not understand that an estimate doesn’t have to be an exact number

• Get stuck and not be able to guess or give an estimate at all

Learn more about different ways kids can struggle with math.

When kids have trouble estimating, families and educators should work together to understand what’s happening. Start by sharing notes on what you’re seeing. Then talk about strategies to try at school and at home. With time and practice, kids can get better at estimating. 

Parents and caregivers: Help your child practice math outside of school, and talk to the teacher about math difficulties you’re seeing.

Educators: Learn more about evidence-based ways to teach math. You can use these teaching practices to help every student learn math at all grade levels.