loop A: 1 to 10
  loop B: 1 to 5
    loop C: 1 to 7

for each iteration of loop A, the loop counter would increase by 35 ( 5 * 7 )

for each iteration of loop B, the loop counter would increase by 7 ( 7 * 1 )

for each iteration of loop C, the loop counter would increase by 1

if loop counter is 80
80 % 35 = 10
(80 - 10) / 35 = 2 - loop A's iteration count

10 % 7 = 3
(8 - 1) / 7 = 1 - loop B's iteration count

loop C's interaction count 3 (innermost loop so mod not required)