Introduction to Subtraction

Learn the basics of subtraction with this free lesson, which includes subtraction basics as well as interactives for you to practice.

What is subtraction?

Subtraction is taking things away. When you have an amount and you subtract from it, the amount becomes smaller. Subtraction happens a lot in real life.

As we saw, if you have 8 eggs and subtract 3 of them, you'll have 5 eggs left. In other words:

8 - 3 = 5

8 - 3 = 5 is a mathematical equation. You could read it like this: five minus three equals two. As we learned in Introduction to Addition, a mathematical equation is basically a math sentence that uses numbers and symbols. When we write a subtraction equation, we use two symbols: - and =.

The minus sign (-) means one thing is being subtracted from another. This is why we put it after the first group of eggs — we had 8 eggs and subtracted 5 of them.

Try This!

Fill in the blanks in the expressions below.

The Equals Sign

The other symbol in our equation is the equals sign (=). As we learned in Introduction to Addition, the equals sign means two numbers or expressions are equivalent, or equal. Even though they might look different, they mean the same thing.

In our eggs example, since 3 eggs were left, we wrote 3 to the right of the equals sign. That shows each side means 3. 3 eggs on the left, and the number 3 on the right. Both sides are equal.

Writing Expressions

As you become more comfortable with reading and writing mathematical expressions, you might notice they are useful for seeing the amount you start with and what you're subtracting.

Any subtraction problem can be turned into a written expression. For instance, let's say your tomato plant has seven tomatoes and you pick four. To figure out the number of tomatoes that are left on the plant, you might write an expression like this:

7 - 4

The expression is just another way of describing the situation: seven tomatoes minus four that were picked.

Try This!

Write these situations as mathematical expressions. Don't solve the problems yet — simply set them up.

You have a pie with eight pieces. You eat two pieces.

You have nine cans of soup and you donate seven to the food bank.

You've gathered six sticks for your campfire. You throw three sticks on the fire.

Solving Problems

In Introduction to Addition, you learned how to use counting to solve addition problems. That skill can also be used to solve subtraction problems.

Ways to Count

We're going to take a look at two ways you can use counting to subtract. First we'll count with objects.

Try This!

Solve these expressions.

7 - 2 =
6 - 3 =
5 - 4 =

Number Lines

Another way to solve subtraction problems is to use a number line.

Practice!

Practice these subtraction problems. There are 3 sets of problems. Each set has 5 problems.

Set 1

3 - 2 =
4 - 0 =
5 - 1 =
2 - 2 =
4 - 3 =

Set 2

6 - 4 =
7 - 6 =
9 - 3 =
4 - 4 =
9 - 1 =

Set 3

10 - 5 =
8 - 4 =
7 - 3 =
9 - 6 =
6 - 1 =

Assessment

Want even more practice? Try out a short assessment to test your skills by clicking the link below:

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