Question 2
Consider the set $A$ of positive 3-digit integers $abc$ consisting of three consecutive, not necessarily ordered, digits.
a) Determine the cardinal of the set $A$.
b) Prove that for any choice of some elements of the set $A$, the sum of the chosen elements cannot equal 2017.
a) Determine the cardinal of the set $A$.
b) Prove that for any choice of some elements of the set $A$, the sum of the chosen elements cannot equal 2017.