Maths help please with slider[SOLVED]

[Splankton]

I have a slider that goes from 0 to 1
which rotates an object from 0 to 90.
To do that, I simply get the slider value every frame, multiply that by 90 every frame, which works perfect.

The problem is my other slider.
That also goes from 0 to 1
which rotates an object from 90 to 0
Now I cant get my head around the math to do the same as my other slider, but instead to rotate from 90 to 0.

I have tried multiplying the slider value by -1 and then multiplying that by 90, that doesnt work, also dividing it. Just cant work it out. I know its something simple, so what is the solution I need?
Thanks for any help

[Splankton]

I solved it,
just a simple thing like it always is. I multiplied the slider value by 90.  Then subtracted the result from that from 90, so it rotates from 90 to 0.