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Chocolate Maths

Age 11 to 14 Challenge Level:

This is cool chocolate maths!!!

bar of chocolate.

  1. 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.
  2. Multiply this number by 2 (just to be bold).
  3. Add 5 (for Sunday).
  4. Multiply it by 50.
  5. Add 1750.
  6. 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.
  7. 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?