Actually, it is a matter of Algebra.

The number of times you like to make love is a variable, so let us denote it as X. When you multiplied that with 50 and then later on multiplied with 200, in effect you multiplied by 10,000 that variable. Therefore, whatever number you deem as the number of times you want to make love will become the ten thousands digit or the first number in that 5-digit number.

Same thing with the age, the same process will result to either 8904 or 8903 where you will subtract the year of your birth, thereby producing your age in the last two digits of that 5-digit number.