Positive and Negative Numbers
You’re probably familiar with positive numbers—you use them all the time in numbers that you give other people, like “go buy 3 apples from the store”—they’re everywhere! You probably know how to add, subtract, multiply, and divide them, and so on. Now, we’re going to give you more numbers to think about—negative numbers. Negative numbers are similar to positive numbers when you count them, but they have a minus sign in front of them, like this: -3. Negative numbers measure how much of something you don’t have, or how much you lack. It can also measure how much you owe someone, especially when dealing with money. Negative numbers are used on the coordinate plane to show direction.
Negative numbers can be counted the same way that regular numbers are counted, you just have to remember to include “negative” in front of them. For example, when counting positive numbers, you say “one, two, three, four” etc, so when counting negative numbers, you would say “negative one, negative two, negative three, negative four” etc. When writing these numbers, you would simply include a negative (minus) sign in front of them, so it would look like this: -1, -2, -3, -4.
Thinking about negative numbers gets tricky sometimes, because the higher you count, the smaller the numbers get. For example, -4 is smaller than -1, even though 4 is greater than 1 when talking about positive numbers. This is because, on the number line, -4 is further away from 0 than -1 is. You can picture it like this:
So, the further you count to the left (past zero) the smaller the numbers get, and the further you count to the right, the bigger they get. This is important to remember because you’ll have to compare negative numbers sometimes, so you need to know which number is bigger and which is smaller. Adding and subtracting positive and negative numbers can also be a challenge, because you have to pay close attention to the signs (+, -) in front of the numbers. Multiplying and dividing positive and negative numbers is challenging, but you can do it if you follow the rules for negative numbers.