How many ways can a four digit number be formed with different restrictions?

[six789]

From the question you wrote, you can't repeat the same number,

ok, i get it...

but this one i don't get it...the last number should be odd because when it's odd, it produces an odd number

 

[Erzeon]

i mean last digit, odd numbers always have their last digit as an odd number.

 

[six789]

ohh, i know what you mean now... so the answer in 4d would be...still figuring out...lol

 

[six789]

is it 9!/5! or 9x8x7x6 for 4d? since the numbers runs from 0 to 9, but there is only 5 odd numbers, and same thing with 4e?