The instructor to my discrete mathematics course gave this question to us. How do you find the smallest achievable value(V) for which all greater values are achievable using only A and/or B, when A and B are relatively prime(coprime). For example for 5 and 7 the answer is 24 (7+7+5+5). Playing around with other values I think the general answer is (A-1)×(B-1) but I'm not sure how to go about proving this. The instructor mention we would use induction but thats it. Thanks for any help.