In our previous lessons we learned all about expressions. We learned how to simplify them using all different types of methods. Now we're going to start looking at equations. Expressions and equations do have a lot of similarities but they are different in a lot of ways too. And as we start moving forward with our lessons with equations it's going to be important to understand how they are different from expressions. So now we're going to use a Venn diagram to do a compare and contrast of expressions and equations. Now, if you look on the left side of the screen we have some examples of expressions and on the right side we have examples of equations. So as we go through and compare and contrast we'll keep looking back and forth at these examples to help us get a better understanding. First, what do they have in common? They both have numbers. We'll normally see some type of numbers. They might be by themselves or they might be with other parts that we call variables. And remember that variables are letters that represent some unknown value or number. We see variables many, many times in algebra. We'll also see operation symbols in both expressions and equations. And those operation symbols can include addition and subtraction signs, multiplication, division signs. We might even see parentheses and exponents. So how are expressions and equations different? Well, expressions do not have an equal sign with them. If you look at all the expressions on the left side there's no equal sign anywhere in any of these expressions. With expressions our goal is to simplify them. We learn different methods for simplifying expressions such as using a distributive property and combining like terms. With equations on the other hand, we will see an equal sign. So if you look at the examples on the right side, each of those do have an equal sign with them and they'll always be something on the left side of the equal sign and something on the right side of the equal sign. Our goal with equations is to solve them. Ultimately, we want to figure out what value that variable represents and this is very different with expressions. With expressions, our goal was never really to figure out what the variable represented. We just tried to simplify the expressions and write them in a simpler way. But with equations our goal is now going to be to solve for the variable and figure out what it represents. So as we move forward with our lessons on equations, just keep this in mind and it'll help you out a whole lot.