This is cool chocolate maths!!!

- First of all, pick the number of times a week that you
eat chocolate. This number must be more than one but less
than ten.
- Multiply this number by 2 (just to be bold).
- Add 5 (for Sunday).
- Multiply it by 50.
- Add 1750.
- Add the last two digits from the year you last had a
birthday. So if your last birthday was in 2009, add 9, if the
your last birthday was in 2011 then add 11.
- Now subtract the four digit year that you were born (if
you remember).
You should now have a three digit number. The first digit
will be your original number (i.e. how many times you eat
chocolate each week). The next two digits give your age. Can
you explain why it works?