Computing : Float vs RealWatch
I don't think it really matters which one you use in the exam. Real numbers, I think, are just another term for floating point numbers (decimals); a float is a single-precision floating point number (so a subset of real numbers).
Really? I've gone through all the past papers multiple times; I thought it always said equivalent names were allowed, or explicitly said something like "Real/float/single/double" in the mark scheme. Maybe I missed it out or something. Still, though, I'd just say write real numbers rather than floats in the exam, just to be safe.