Solve the problem - How many three digit numbers do not contain a five? Show evidence of solving the problem in a systematic way.

Answer 1

try figuring

how many do contain a five?

Then subtract that from the number of 3-digit values.

Answer 2

So we only have 8 digits to choose from for our leading digit, then 9 digits for each of the remaining spots

number of three digit numbers with no 5
= 8x9x9
= 648