Yea its me. I also post the same question in

dream.in.code.

As you said, expressing a fraction in base10 as rational number, then converting the bases of numerator and denominator and then divide them to find corresponding fractional representation in that base. But the problem is that, the division has to be done by the rule of that particular base, not the ordinary decimal division. Isn't it? This is too difficult I think as I am handling too many bases. I need a general rule of division applied to all bases. I am afraid there is no such rule as per my knowledge.

Actually I am designing a calculator, a scientific calculator, I gave its name Super Scientific Calculator. If I could make the Negabase conversion possible, then there will be a choice of conversion between 72 bases (-2 to -36 and 2 to 36). And many more other functions, Complex number, various number theoretic applications etc. I will look forward to hear from you.

Thank you.