i thot i was bad at this but then solved in 30 seconds. my thinking goes like this.. if the num is less than 100, then you should find the factor less than 50 because, 2 is the least prime factor, so if 2 is a factor then 50*2=100, so search for a num less than 50, now look for a prime number less than 50.. and the first prime num u wud fine less than 50 is 47.. so if you have a number.. 94.. then its factors are 2, 47, 94.. so you have 47-2= 45.. hope thats corrrect..