It is common knowledge that floating point numbers (float) are tricky. When misused, floats may lead to construction disaster - I will mention some notable accidents. But mainly, I will dig the topic from Python interface and rounding methods (int vs round, divmod, math library), via special symbols (NaN, Inf, -0.0, …), invoking different processor modes (FLT_ROUNDS), down to the bits of IEEE 754 standard.