Question

Greg purchased n notebooks. They were 4 dollars each. Write an equation to represent the total cost c that Greg paid.

Answer 1

c = 4n

Explanation:

The total cost (c) is going to be of the 4 notebooks together

We don't know how many notebooks Greg got, so it's represented by n.

It doesn't matter how many notebooks Greg purchased, because each of them were $4.

So to represent the total cost of the notebooks, you would write c = 4n

Answer 2

It might help you to think about what you would do if you were given a specific number of notebooks. If he bought 5 notebooks, it would cost 5 * 4 = 20, right? If he bought 3, you would multiply 3 * 4. Whatever number he bought, you would multiply it by 4 to see how much it would cost. So if n is the number bought, the cost will by 4 * n,or to write it more simply, 4n.
Make sense? If not, ask more.
Mary