__Objectives:__

- Define an integer.
- Recognize the importance of integers in the real world.
- Use a set of rules to add, subtract, multiply, and divide integers.

__What is an integer?__

An integer is a whole number that can be negative or positive (but cannot be both at the same time).

Examples include -100, 50, 8, 325

All of these numbers are all whole numbers. This means that they are not a fraction or a decimal.

All of these numbers are all whole numbers. This means that they are not a fraction or a decimal.

If we look at the blue dots on the number line above, we can see that these values are integers. The values inbetween the integers would be fractions and decimals. We can also see that negative integers are to the left of zero on the number line. In comparison, positive integers are to the right of zero on the number line.

__Why are integers important?__

Integers play an important role in our everyday life. Without integers, we wouldn't have a way to keep track of numerical values. We use integers when we go grocery shopping, balancing our checkbooks, checking the temperature, and etc. They're everywhere! Think about the ways that you use integers!

__Adding Integers using Rules__

We can add integers by using the addition rules. These rules are:

I like to remember that when adding the "same sign", I will keep the sign. Hence, if I am adding two positive numbers together then I will keep the sign positive. Same goes for when adding two negatives together. I will keep the negative sign.

__Subtracting Integers using Rules__

Subtracting integers is very similar to adding integers. This is because when we subtract integers, we will "add the opposite". This changes the problem to an addition problem. Let's look at the following examples!

__Examples__

Simplify by performing the given operation:

__Multiplying & Dividing Integers using Rules__

Now, we will move onto multiplying and dividing integers. Multiplying integers is similar to dividing integers because when the "same sign" is being multiplied or divided, then the result will be positive. The multiplication or division of "opposite signs" will result in a negative. Let's look at some examples:

__Examples__

Simplify by performing the given operation:

## Quiz

(C) 2017 MATH IN DEMAND