Hi,
I've never seen strictfp used in any real-world coding but I understand that it is used to indicate that any floating-point maths must conform to the IEEE 754 standard, so all values must be expressed as float and double and any internal values can't use platform-dependent formats that may give you extra range or precision. This is so that you can predict what any rounding errors will be.
As long as you know it can be applied to a class or method only, this is all you'll need for the exam.