there are a few questions like this and Im having trouble with them.

a multiple choice test has 5 questions, with 4 possible answers per question, how many ways are there to complete the test?

I havent done any of this type of math in a long time so Im stumped.

I know it has something to do with multiplying the number of questions by the number of possible solutions per question?

I aslo did one other question but the book is giving me the wrong answer but I could swear I did it right.

it is.

how many 2 digit whole numbers can me made using the numbers 1,2,3,4,5,6,7,8 with no repetitions.

I could do the one with repatriations.

=8x4=32

but without repetitions I get an incorrect answer.

I do 8x3=24, but the answer is 28

I do that because there are 8 possible digits for the ten's and 4 possible for the one's, and I thought you subtracted one from the one's so there are no repetitions? I understand If I took 1 away from 8 and multiplied it by 4 its 28 but why?

thanks