DATE: September 15, 2008
TOPIC: two-step equations
OBJECTIVE: we will be able to solve two-step equations.
WHAT IS AN EQUATION?
An equal sign (=) is like a scale: the things on either side are exactly the same. For example, 2+2 = 4. If I have $2, and my friend Mark has $2, that is the same as having a total of $4.
In an equation, we need to figure out a missing number in order to figure out how to make the things on either side of the equal sign exactly the same. That missing number is called a VARIABLE. We use letters to show a variable. For example, 2 + n = 4. The "n" is our missing number. It is our variable.
When we talk about solving an equation, all we really want to do is find out what number the variable is. For example, in the equation 2+ n = 4, we know that the variable is equal to the number 2. We know this because if we took out the "n" and replaced it with a "2", we would get 2 + 2 = 4. In this case, both sides of the equation are equal. That's exactly what we want to find!
UNDERSTANDING QUESTIONS:
1. The two things on either side of an equal sign (=) are always ____________.
2. In an equation, we are trying to find a ________________.
3. We represent variables with ______________.