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Understanding the Subtraction Sign

This lesson explains what the subtraction sign (minus sign) means, how it fits into a subtraction sentence, and how it connects to the idea of taking away or finding the difference between two numbers, with number line pictures and simple worked examples for early learners.

What Does the Minus Sign Mean?

The minus sign, written as \( - \), is the symbol that tells us to subtract. Subtracting means taking some objects away from a group, or comparing two amounts to see how many more one has than the other. Whenever you see the minus sign between two numbers, it is asking, "what is left over?" or "what is the difference?"

For example, in the sentence \( 7 - 3 = 4 \), the minus sign tells us to start with 7 objects and take 3 of them away. What remains is 4.

The Parts of a Subtraction Sentence

Every subtraction sentence has three parts. Look at \( 7 - 3 = 4 \):

7 is the number you start with (the whole group).
3 is the number being taken away, right after the minus sign.
4 is what is left, written after the equals sign.

The minus sign always sits between the starting number and the number being taken away. Reading it out loud, we say "seven minus three equals four."

Seeing the Minus Sign on a Number Line

A number line is a helpful way to picture what the minus sign does. To subtract, you start at the first number and hop backward, one space for each number being taken away.

Starting at 7 and moving back 3 spaces lands on 4, so \( 7 - 3 = 4 \).

Every time you move one space to the left, you are subtracting one more. The minus sign tells your finger which direction to hop: backward, toward zero. You can see this idea worked out step by step in using number line to subtract up to 20.

The Minus Sign Compared to the Plus Sign

The plus sign \( + \) means to join groups together and move forward on the number line. The minus sign \( - \) does the opposite: it means to remove part of a group and move backward. Keeping these two signs and their directions straight is one of the most important habits in early math.

Practice Reading and Using the Minus Sign

Try reading each sentence below out loud, saying the word "minus" for the sign:

\( 9 - 2 = 7 \), read as "nine minus two equals seven."
\( 5 - 5 = 0 \), read as "five minus five equals zero." You can explore what happens when the two numbers match in subtracting with the number zero.
\( 12 - 6 = 6 \), read as "twelve minus six equals six."

Once reading the sign feels comfortable, you are ready to move on to counting strategies and fact families, such as those covered in subtraction facts up to 20 and subtracting with digits up to 20.

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