How Do You Subtract Signed Numbers (Integers)?
Subtracting signed numbers can be tricky, especially because there are many different ways to do it. The method that is taught by your teacher might be different than what you see in a review book or on a website. In this article, I will show you a simple method which always works. Our procedure for subtracting signed numbers is to convert the problem into an equivalent addition problem. Then we can follow the rules for signed number addition (see other article) Let’s look at the problem (-2) – 5. The first thing to do is leave the first number alone. The second step is to change the subtraction operation to an addition operation. The last step is to change the sign of the second number. If it is positive, make it negative, and vice-versa. In this problem, after doing these steps, we get (-2) + (-5). Now we can add according to the rules for signed number addition (see other article). In this case we get -7 as an answer. Let’s try one more: (-8) – (-5). That may look scary, but let’s f
