I received this in a humor newsletter. I’ve seen several variations but I have yet to understand how this works mathematically. Does anyone know?

It’s probably best to try it before you read too much further (in case someone is able to explain it) because like magic tricks, they’re usually not nearly as impressive after you know how they work.

1. First, pick the number of times a week that you would like to have chocolate (more than once but less than 10)

2. Multiply this number by 2 (just to be bold)

3. Add 5

4. Multiply it by 50

5. If you have already had your birthday this year add 1756 .. If you haven’t, add 1755.

6. Now subtract the four digit year that you were born.

You should now have a three digit number.

The first digit of this was your original number (i.e., how many times you want to have chocolate each week).

The next two numbers are your age!

I decided to run the numbers and I can see that it ends up with 2006 (or 2005) plus the number you chose times 100. I still don’t understand what the times 2 and plus 5 do exactly and how someone was able to derive the equation.