1) How many six-digit odd numbers can be formed using all the digits 0, 1, 2, 3, 4 and 5? (Use only the numbers listed, no repeats)

2) Ten people each randomly select a number between 1 and 20. What is the probability that at least two of them select the same number?

3) Ms. Jenny has 5 students writing a exam. She forgot to put a place for the students to write their names and all the tests were handed in before she noticed the mistake. She thinks she has a pretty good chance at guessing randomly! What is the probability she enters all the marks incorrectly?