Assignment: 08-Writing an Equation
The idea behind this lesson is to get us a little more familiar with story problems. We need to be able to take the information in the story problem and turn it into the expression and equations that we have been working with. If we have a word problem such as:
If I have 6 eggs, how many do I need to make a dozen?
We can easily interpret this information to know that we need 6 eggs, but as the story problems get more difficult, we need to be able to take the words and turn it into an equation, so we practice this with easier problems first, before we move to more difficult equations.. To turn a word problem into an equation, we follow this basic pattern:
(What You Have)(What Expression You Do)(Variable) = (Total Number)
The variable represents what you are trying to find. You can pretty much choose any letter you want for it, but we usually try to choose a letter that corresponds with what we are talking about. Using the previously mentioned question, we would fill in that information accordingly:
What You Have: 6 Eggs
Expression: +
Variable: e (for how many eggs you need)
Total Number: 12 eggs
If you put those into the pattern for the equation, your equation would look like this:
6 + e = 12
Here’s another example:
Sam bought 8 ball caps. She spent a total of $64. How much did each ball cap cost?
What You Have: 8 ball caps
Expression: * (Remember the star is another symbol for multiply)
Variable: m (for money per cap)
Total Number: $64
The equation would be: 8m=64 (Remember, again, that a number right by a variable means multiply as well.)