Help with a simple color slider?

I have this simple color slider GUI that gives me a number between 0 and 1.

However I need to convert that one number to seperate RGB values. I’m fustrated by this because it sounds so simple yet I can’t solve the problem.

e.g

0 = 255, 0, 0

0.5 = 0, 255, 255

1 = 255, 0, 0

You can see for yourselves if you search “color picker” in google.

Please help, thank you.