How many permutations of three different digits (3-digit numbers) are there, chosen from the ten digits 0 to 9
inclusive? (No replacement)

In simplified exponential notation, the expression a^2•a^-3•a 1/a 0

Which of the following expressions are equivalent ?

You have $600,000 saved for retirement. your account earns 5.5% interest. how much, to the nearest dollar, will you be able to pull out each month, if you want to be able to take withdrawals for 20 years?