Let's say we want to store numbers in computer memory but we are not allowed to use decimal point or any characters except for digits. We need to make some system to encode and decode real numbers as a sequence containing only digits.

With fixed point numbers, you write the digits into the memory and have a convention that the decimal point is always after N-th digit. For example, if we agree that the point is always after 2-nd digit then a string 000123 is interpreted as 00.0123 and 123000 means 1230. Using this system with 6 digits we can represent numbers from 0 to 9999 to precision of 0.01.

With floating point, you write both decimal point position (which we call "exponent") and digits (called "mantissa"). Let's agree that the first two digits are the exponent (point position) and the rest four is mantissa. Then this number:

    020123 

means 01.23 or 1.23 (exponent is 2 meaning the decimal point is after 2nd digit in mantissa). Now using same 6 digits we can represent numbers from 0 to 9999·10⁹⁶ with relative precision of 1/10000.

That's all you need to know, and the rest should be easy to figure out.