Her error was that she thought 0.1 and 1/4 were negatives but they are still positive.
She also thought the larger the negative the greatest one. The smaller negative is the greatest because it's bellow 0.
To solve this you would first need to turn 1/4 into 0.25
It would start out with -2 cause that is the least. Then -1. Now its back to positive so the least to greatest would be normal.
So the real answer would be -2, -1, 0.1, 1/4