General Combination question regarding 0

[g.shiqian]

Whenever a problem says how many ways can you form an X digit combination, are you to assume that 0 is a viable candidate?

For example if someone says how many 3 digit combos can you have beginning with an Even numbers. Are you allowed to use 0 as any of the digits and if so, can you use 0 as an Even #?

Thanks!

[RonPurewal]

i've never seen the phrase "N-digit combination" or "combination of N digits" in an official problem.

if you're referring to an N-digit number, then, no, you wouldn't include these cases. for instance, 8 is a one-digit number; you can't write it as 008 and claim that it's a three-digit number.

--

as for the number 0 itself, the gmat is not going to ask you about such a thing; the gmat NEVER includes questions that are based on the funky boundaries of definitions.
in fact, the test doesn't even touch definitional boundaries that are universally accepted but still weird. for instance, it is universally accepted in mathematics that (a) 1 is not prime and (b) 0! = 1, but the gmat will not test these things.

[g.shiqian]

Thanks Ron!

[tim]

:)