Floats are pretty hard, especially if you're accepting exponentiation: - 1.4 - -1.4 - .4 - -.4 - 1. - -1. ... plus exponents, also you don't need a decim

Floats are pretty hard, especially if you're accepting exponentiation: - 1.4 - -1.4 - .4 - -.4 - 1. - -1. ... plus exponents, also you don't need a decimal point if there's an exponent Won't Ruby parse a string into a float? I would just use that and check for an error unless your requirements are different.