This is a combinatorics problem I must solve:
How many even numbers between 10,000 and 20,000 have distinct digits(i.e no repetitions)?
Is the way I solved it correct?
I put for lines for the numbers :
_ , _, _ ,_ , _
And I put numbers in each spot: 1, 8, 7, 6, 4
Multiplying out I get 1,324 . Is this the right way to go?