I'm lost on these two.
7. How many different 7-digit number begin with an odd digit, end with an even digit, and do not repeat any digit for the remaining three digits?
11. How many ways are there to distribute 30 identical pens among four students so that the first student receives at least 3 pens, the second at least two pens, and the fourth receives EXACTLY four pens.
The "exactly" part threw me off in this one.
Help? thank you!