1a Complete the multiplication table modulo 7

Question

x 1 2 5 6
1 1 2 5 6
2 2
5 5
6 6

1b. From the table evaluate {1*2}*{2*6}

Answer 1

(mod 7) just means you use the remainder when dividing by 7
3*5 = 15 (mod 7) = 1 because 15 = 2*7 + 1
and so on