Q: Find value on scale of 0 to 1 including negative and positive numbers I've been mulling this issue in my head for a few hours. I'm sure its quite simple, but I'm having trouble breaking exactly what I need to here. (Its been many years since my college days, and I don't need to do anything beyond basic addition and subtraction much anymore!).
I have a range of numbers that can be anywhere on the negative or positive scale (ex: -20,000 & 160,000, or -200,000 & 0, or $-240,000 & -200,000)
I have to locate, in a scale of 0 to 1, 5 other numbers within this range. 0 is the low end, 1 is the high end. To take an easy example, if the two numbers are -200,000 & 0, and the number within the range I need to find is -180,000, then -180,000 would come out to .10.
Where I'm struggling is figuring this out when the range spans negative and positive numbers. (ex: From -20,000 & 160,000, where would -1,800 fall? Where would 153,000 fall?) Any help is appreciated - the simpler, the better please!

A: Try $\dfrac{(-1800) - (-20000)}{160000-(-20000)} \approx 0.10111\, $ and $\, \dfrac{153000 - (-20000)}{160000-(-20000)}\approx 0.96111\,$ 
More generally you can use $$\dfrac{\text{number of interest}-\text{bottom of scale}}{\text{top of scale}-\text{bottom of scale}}$$ remembering that $-(-x)=+x$
