"-1 modulo 25" is "1 less than a precise
multiple of 25".
So what are the exact or precise multiples of 25 in the appropriate
interval?
It is -75, -50, -25, 0, 25, 50, 75, and 100.
Now just subtract 1 from each of them.
So the answers are -76, -51, -26, -1, 24, 49, 74, and 99.
They are both right becuase if you just take away 1 from 20 and 10 you get 2 and 1. For the 4:2 one take away 1 and mutiply by 2 equalling 4:2 but they are still the same thing.
