In this lesson on algebra negative numbers are covered. Get information and negative numbers practice here.

Using negative numbers in arithmetic is fairly simple. There are just a few special rules to keep in mind.

When you're adding and subtracting negative numbers, it helps to think about a number line, at least at first. Let's take a look at this problem: **6 - 7**. Even though 7 is larger than 6, you can subtract it in the exact same way as any other number, as long as you understand there are numbers **smaller** than 0.

6 - 7 = -1

While the number line makes it easy to picture this problem, there's also a trick you could have used to solve it.

First, ignore the negative signs for a moment. Just find the **difference** between the two numbers. In this case, it means solving for **7 - 6**, which is 1. Next, look at your original problem. Which number has the **highest absolute value**? In this case, it's -7. Because -7 is a negative number, our answer will be one too: -1. Because the absolute value of **-7** is greater than the distance between **6** and **0**, our answer ends up being **less than 0**.

How would you solve this problem?

6 + -7

Believe it or not, this is the exact same problem we just solved!

This is because the plus sign simply lets you know you're combining two numbers. When you combine a negative number with a positive one, the sum will be **less** than the original number—so you might as well be **subtracting**. So **6 + -7 ** is the same thing as **6 - 7**, and they both equal -1.

6 + -7 = -1

Whenever you see a positive and negative sign next to each other, you should read it as a **negative**. Just like 6 + -7 is the same as 6 - 7:

**10 + -11**is equal to 10 - 11.**3 + -2**is equal to 3 - 2.**50 + -100**is equal to 50 -100.

This is true whenever you're adding a negative number. Adding a negative number is always the same as subtracting that number's absolute value.

If adding a negative number is actually equal to subtracting, how do you **subtract** a negative number? For example, how do you solve this problem?

6 - - 3

If you guessed that you **add** them, you're right. Here's why: Remember how we said a negative number was the opposite of a positive one? We compared them to you and your mirror image. Your mirror image is your opposite, which means your mirror image's opposite is **you**. In other words, the opposite of your opposite is **you**.

In the same way, you can simplify these two minus signs by reading them as two negatives. The first minus sign **negates**—or makes negative—the second. Because the negative—or opposite—of a negative is a positive, you can replace both minus signs with a plus sign. This means you'd solve for this:

6 + 3

This is a lot easier, to solve, right? If it seems confusing, you can just remember this simple trick: **When you see two minus signs back to back****, replace them with a plus sign**.

So **6** minus **negative 3** is equal to 6 plus 3. That's equal to 9. In other words, **6 - -3** is 9.

Remembering all of the rules for adding and subtracting numbers can be overwhelming. Watch the video below for a trick to help you.