> But if the exponent’s significant bit goes from 1 to 0, why would that affect the mantissa at all? It's not a matter of the "significant bit", but whether th

> But if the exponent’s significant bit goes from 1 to 0, why would that affect the mantissa at all? It's not a matter of the "significant bit", but whether the WHOLE exponent is 0 or not. An exponent of 0 is a special case; as soon as you set ANY bit in that exponent, the mantissa goes back to the "implicit 1" prepended bit. > Also, if the significant bit is always 1, how are negative exponents represented? Exponents are represented in a "biased representation", counting up from 2-127. > I understand there’s an implicit “hidden” bit, but what conditions cause it to become 0 instead of 1? Exponent bits being all 0. > And does that bit represent the sign of the exponent, or something else? It represents the leading bit of the mantissa.