How many four digit numbers can be formed from the digits from 1 to 9 inclusive, if repetitions are not allowed?
i. How many of these are divisible by 5?
ii. How many are divisible by 2?
iii. How many of these contain digits in ascending order eg 1459?
I've done i and ii and i got 336 and 1344 but I'm confused about how to do part iii.