The question asked how many combinations of digits 1-5 can be made in 2 places, less the number of repeating digits (22, 33, etc). The answer book says 20, which does not make sense to me since one can count out 40 combinations without doing any math (10 thru 19, not counting 11, and so on through 59.

What am I doing wrong?

nevermind- I see my mistake....must be too much drinking

lol - no problem! Glad you found your mistake yourself - that's always the best way!