2. Expressions
Unit 3 is all about expressions. Here, we talk about different ways to express something else.
For example, I might ask you to call a dog that lives with you a name. If I called the dog Spot, then the name Spot is merely an expression of a dog that lives with you.
Or perhaps you’ve seen me get mad. My angry face, is an expression of how I am feeling.

3. Expressions continued
Math uses expressions too.
For example, I might say the number 2 could be represented by
Or, I might say that ½ is an expression of .5
In other words, an expression is just another way to represent something else

4. Intro to Exponents
A special expression that we use in math is called an exponent.
An exponent is an expression. It is another way to write a number.
You’ve probably seen exponents before… it looks like a big number and a smaller, tiny number just above and to the right of the bigger number.
Let’s talk a little bit about each of these parts of the expressions

5. Exponents… In this expression, we are going to show that the
Number 25 can be expressed in another way.
See the big number to the right? It is called a base.
The smaller number above and to the right is called
The exponent.
Finally, the entire expression is called a power.
So how do I use exponents???

6. In the previous expression, the base is the number that you are multiplying by. It is a number that you will multiply to itself.
The exponent represent the number of times that you multiply the base to itself.
Remember, the entire thing (both the base and the exponent) is called a power.

7. So now, lets use this example to see what I mean.
Here, we use the base 5. Then, I multiply the base times itself by the number of the exponent. Here, it is 2 times.
So, in this expression, you would multiply 5 times 5.
Why? Because 1 five times 1 five = 25

8. Examples: Lets try a few examples… (write some on board)
Try 5 different examples… be sure to show that a fraction can also be a base!

9. Careful! DO NOT SIMPLY MULTIPLY THE BASE BY THE EXPONENT.
THIS IS WRONG. YOU HAVE TO MULTIPLY THE BASE BY ITSELF SOME NUMBER OF TIMES.

10. A FEW rules… 1. Always multiply the base by itself.
2. A power with an exponent of 1 is…simply the base.
3. A power with an exponent of 0 is…always 1.
4. A fraction can also be a base.