Exercise
The numbers 12 and 27 are congruent modulo
1, 3, 5 and 15
1, 3, 5, 6 and 9
0, 3, 5 and 15
Correct! All these numbers are positive integers dividing 27 - 12 = 15
No, 6 is not a divisor of 27 - 12 = 15
Wrong, because division of 27 - 12 by 0 is illegal