The math problem: If she writes 6 checks for exactly $19.98, what expression describes the change in her bank account?

My Thoughts: I know the answer is 6 (-19.98)

My Question: What key word in the problem shows that each check is $19.98, and not the 6 checks in all?

Your key "word" is the parentheses () that encloses the - 19.98. In this case, think of the parentheses as saying multiplication. It means that in all equations, btw.

so, I write six checks at 19.98. The negative sign in front of the 19.98 signifies a decrease in the checking account for each check written