• Root causes
• School struggles
• Math

# Why kids struggle with estimating quantities

By Andrew M.I. Lee, JD

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How many juice boxes do we need for the party? About how many coins are in the jar? Estimating “how many” is a math skill we use almost every day. It’s also a skill that many kids struggle with.

A big reason kids have trouble estimating “how many” is because they haven’t learned basic math skills like number sense. Number sense is a set of skills that help you understand how numbers relate to each other, like if 10 is more or less than 5. Without these skills, estimation is very difficult.

Even when they know the basics, kids might still struggle if estimation hasn’t been clearly explained to them. They may think numbers have to be exact. And they may not have had enough practice trying to guess different quantities.

All kids develop differently. Some pick up math skills and learn how to estimate with just a bit of teaching. Others need extra practice and time to learn. And some kids continue to struggle with estimating even after teaching and practice.

This could be a sign of an underlying challenge in math. A common one is a learning difference called dyscalculia. See a list of signs of dyscalculia .

## Dive deeper

### Basic math skills for estimating

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.

### What trouble estimating looks like

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

### Next steps

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.

### Related topics

• Root causes
• School struggles
• Math

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