Np. So each table has done the math for you and has calculated a number (factor) for you to use based on your intentions. In this case, you've figured out that we need the Future Value and it is not an annuity. If you look at the future value table, you see that is asks for # of periods and interest rate. We know both. Now, instead of doing a manual calculation or even using a financial calculator, we can locate the factor that intersects with our n and i. Then, we can take that value and multiply by our principal amount of $20,000 to find the future value. Then compare that to the vacation cost to answer the question.

These tables are a shortcut to finding the namesake values.