How to Teach Subtraction to Kids: A Step-by-Step Guide

Put five grapes on a plate and ask your child to eat two. Then ask, “How many are left?” Let them count what’s still on the plate. That’s subtraction, and a snack is a fine place to start today.

The steps below suit ages 4 to 8, roughly preschool to grade 2. Ages are a rough guide only. Some children move through a step in a week and others need a few months, and both are normal.

What order should you teach subtraction in?

Subtraction has two everyday meanings and a few ways of working it out. Teach the meanings with objects first, then the quicker ways. US school standards (the Common Core) follow a similar path: subtracting with objects in kindergarten, strategies such as counting and making ten within 20 in grade 1, and fluent subtraction within 20 using mental strategies in grade 2.

You don’t need to say the names of the steps to your child. Watch what they do, and show the next way when the current one looks easy.

Before subtraction: what does your child need first?

Your child should be able to count a small group, touching each object once, and know that the last number tells how many. If counting still wobbles, start with how to teach counting to preschoolers.

It also helps if adding with objects already feels easy. Subtraction undoes adding, and the two grow together. Our guide on how to teach addition to kids covers the adding steps that pair with these.

The words matter too. Use “left”, “fewer”, “how many more” and “the difference” during play, long before the minus sign shows up.

“You had 4 blocks. You gave me 1. How many are left?”

Step 1: what is take away? (ages 4 to 6)

Take away means starting with one group and removing some. Seven birds sit on a fence, three fly off, and four stay. It’s the meaning most children meet first, because it’s something they can do with their hands.

Kindergarten standards say children show subtraction “with objects, fingers, mental images, drawings” and other concrete ways, and solve word problems within 10 (K.OA.A.1 and K.OA.A.2). So keep it physical:

• Snacks. Six crackers, eat two, count what’s left.
• Fingers. Hold up 8, fold down 3, count the fingers still up.
• Toys in a box. Put 5 cars in a box, take 1 out to play, count the rest.

Keep the start number at 5 or less at first, then go up to 10. US standards expect subtraction within 5 to be fluent by the end of kindergarten (K.OA.A.5).

Have your child tell the story back to you. “There were five, I took two, now there are three.” Saying it out loud links the action to the number.

Step 2: what does compare mean in subtraction? (ages 5 to 7)

Compare starts with two groups and asks how many more one has than the other. Your child has 7 red cars and 4 blue cars. Nothing is taken away, yet it’s still subtraction: 7 - 4 = 3, so there are 3 more red cars.

Many children find this harder than take away. The question “how many more?” contains the word “more”, which sounds like adding. Grade 1 standards list comparing as one of the story types children solve within 20 (1.OA.A.1), so it’s worth teaching on purpose.

The trick is to match the two groups. Put the red cars in one row and the blue cars in a row under them, one under each.

Each red car with a blue partner is a pair. The red cars with no partner are the difference. Count them: 3.

Try both meanings below. In Take away, tap counters to cross them out and watch the number sentence change. In Compare, tap Show pairs and count the counters left without a partner.

Steps 3 and 4: should your child count back or count up? (ages 5 to 7)

Once objects feel easy, your child can subtract by counting. There are two ways, and each one suits different problems.

Counting back works when the number taken away is small. For 9 - 2, your child says “nine” and counts back two: “eight, seven.” The answer is 7. Grade 1 standards link counting to subtraction in just this way (1.OA.C.5). A number line helps: stand on 9 and hop back twice.

Counting up works when the two numbers are close. For 12 - 9, counting back nine steps is long and easy to lose track of. Instead, start at 9 and count up to 12: “ten, eleven, twelve.” That’s 3 counts, so 12 - 9 = 3. It’s the compare idea again: how far is 9 from 12?

Grade 1 standards describe this as treating subtraction as a missing addend, for example finding 10 - 8 by asking what number makes 10 when added to 8 (1.OA.B.4).

A simple rule for your child: look at the number you take away. If it’s small, count back. If it’s close to the first number, count up. Write 15 - 2 and 15 - 13 side by side and ask which way is shorter for each.

How does subtraction connect to addition?

Every subtraction fact has an addition fact hiding inside it. If your child knows 3 + 5 = 8, they also know 8 - 5 = 3 and 8 - 3 = 5. These four facts are called a fact family: 3 + 5 = 8, 5 + 3 = 8, 8 - 3 = 5 and 8 - 5 = 3.

This is how most children end up knowing subtraction facts. They don’t learn each one separately. They think, “What goes with 3 to make 8?” Our guide to number bonds explained shows how to teach these part and whole pairs with objects.

Pairs that make 10 are worth extra time. If 10 = 7 + 3, then 10 - 7 = 3. Fill a ten frame with 10 counters, take 7 away, and the 3 left make the link easy to see. The same pairs help with problems that cross ten. Grade 1 standards give the example 13 - 4 = 13 - 3 - 1 = 10 - 1 = 9: take 3 to get down to 10, then 1 more (1.OA.C.6).

Linking the two isn’t automatic. In a study of 44 children aged 6 to 7, Dowker (2014) found that using the link between addition and subtraction was among the hardest strategies for children to use. Some subtraction problems also often drew wrong answers that carried an addition rule into subtraction (see the mistakes section below). We suggest showing each link with objects, not just saying it.

By the end of grade 2, US standards expect children to subtract within 20 fluently using mental strategies (2.OA.B.2).

How do you move from objects to the minus sign?

Bring in the written number sentence only after your child can subtract with objects. Go one small step at a time:

1. Objects and words. “Six crackers, I ate two, four are left.”
2. Drawings. Draw six circles and cross out two.
3. Numbers by the drawing. Write 6 above the circles, 2 by the crossed-out ones and 4 by the rest.
4. The number sentence. Write 6 - 2 = 4 and read it as “six take away two is four.”

Read the minus sign in different ways so it doesn’t only mean “take away”: “six minus two”, “the difference between six and two.” Order matters here too. 6 - 2 is not the same as 2 - 6, which is a good thing to show with real crackers.

Little stories keep the numbers meaningful. “Pip had 9 berries and ate 4. How many are left?” is take away. “Pip has 9 berries and a friend has 4. How many more does Pip have?” is compare.

Both are 9 - 4 = 5. Grade 1 standards also ask children to find the missing number in problems like 5 = ? - 3 (1.OA.D.8), so try a few stories where the start is the unknown: “Pip ate 3 berries and 5 are left. How many were there at the start?” Putting the 3 back with the 5 gives 8.

For dice and track games that practise subtraction, see our list of math games for kids or the kindergarten math games for ages 5 to 6.

What are common subtraction mistakes, and how do you fix them?

• Counting the start number. For 9 - 3, your child says “nine, eight, seven” and answers 7. They counted the 9 as one of the steps back. On a number line, show that you stand on 9 and only count when you land: eight, seven, six.
• Adding in a compare story. “How many more?” sounds like adding. Act it out with two rows of objects before writing.
• Swapping the numbers. Asked 2 - 6, some children answer 4 because they always take the smaller number from the bigger one. Show with a plate of 2 crackers that you can’t take 6 away, and that 6 - 2 is a different question.
• Carrying an addition rule over. A child who knows 9 - 3 = 6 may say 9 - 4 = 7, because in adding, one more in gives one more in the answer. Dowker (2014) reported this kind of mistake often. Show with objects that taking away one more leaves one fewer: 9 - 4 = 5.
• Zero and same-number problems. 5 - 0 and 5 - 5 can puzzle children. Take away nothing: still 5. Take away all of them: 0 left. Try both with a real plate.
• Guessing. The step is usually too big. Go back to objects or smaller numbers for a few days and finish on a problem your child gets right.

The short version

Teach both meanings of subtraction, take away and compare, with real objects. Then add counting back for small numbers taken away and counting up when the numbers are close. Finally, link each fact to the addition fact your child already knows. Keep sessions short and go back a step whenever guessing starts.

When hands-on subtraction feels easy and you’d like more practice with number sentences, Math Learner is a math practice app for children aged 3 to 10. Its Subtraction world uses number sentences with four answer choices, and the early levels never need borrowing across ten. Each level has eight questions, and a wrong answer shows the right one. The first 15 levels of each world are free, one lesson a day.

It has no ads, no account and no tracking tools. You can download it here and try a level together.