Thread: Lottery question

"In a weekly lottery, a player selects six different numbers from 1 to 40. Determine the number of possible lottery tickets."

I answered 40 * 39 * 38 * 37 * 36 * 35 = 2,763,633,600. The book says 3,838,380. If the book is right, why?

Order doesn't matter, so C(40,6)=3838380