Question

M is a 2 digit number ab and N is a 3 digit number cde and 9xMxN=abcde. Find M and N

Answer 1

1) Two 2-digit numbers sum to a 3 digit number in the form AAA. Since AB < 100 and CD < 100, AB + CD must be less than 200. So AAA = 111, and A = 1.

2) Now we know, since A is equal to 1, that AB < 20. The only way that AB + CD = 111, if AB < 20, is that if CD > 90. Therefore, C = 9.