2/1 is the fraction always as a whole number the whole number goes on top and always the 1 goes on bottom for every whole number Hope that helped have a good day! :)
If u wrote 9 to the power of - 2 and x to the power of - 1 and y to the power of 0 and write the x at then end it would end up a fraction of 1/81 but I'm not sure what u want like multiply?
The black line is shorter than the gray. Let's simplify the rules. (B=Black, W=White, G=Grey
B is less than W which is less than G
That means G is greater than W. B is less than W, which is less than G. Therefore, the black line is not only shorter than the Gray one, but also the shortest out of the three.
I hope this Helps!