what on earth is the formula?

hi im kate, and i need help. we are playing this game (Luffa Lotto) which the no.s are 1,2,3,4,5,6,7,8,9,10. a combination is 1,6,3. another is 9,5,3. 4,6,4 can not be one 'cause there are two fours. we have got to work out how many combinations there are altogther, and we need the formula to work it out. if you know please help me!

thanks soooooooooooooooooooooooooooooooooooooo much

bye :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: :confused: