Question 8604
I MUST ENTIRELY AND COMPLETELY DISAGREE ON THE SOLUTION TO THIS PROBLEM!!  The solution previously posted is absolutely WRONG!!  A divisibility rule for 14 consists of determining if a number is divisible by the ALL FACTORS of 14, which would be 2 and 7!!  It has NOTHING TO DO WITH DIVISIBILITY by 9 and 5!  


Likewise, divisibility by 15 requires that a number be divisible by 3 and 5. 


Divisibility by 18 requires divisibility by 2 and 9, and divisibility by 20 requires divisibility by 4 and 5.  I don't know the divisibility rules for 13, 17, or 19.  Maybe someone else can add solution for those. 


R^2 at SCC