How do I make a "Reverse lerp"

Instead of going 1 0.5 0.2 0.1 0.05...

How do I go 1 0.00001 0.0001 0.001 0.01 0.1 0.2 0.5...

I know it's mathematically impossible because the limit of decimals is infinite but is there a way I can simulate something like it?

Lerp(a,b,c)

The target value is b depending on a percentage given by c, so you would just change the target value via a variable, so there's no reason to think it's impossible, aside from using ridiculously small values that is.

100 percent of 0.00001 is 0.00001