I KNEW I shouldn't have asked.
Last week, I told how you could tell your age from your shoe size. Let me recap: multiply your shoe size by five, add 50, multiply by 20, add 1012 and subtract the year you were born. When you get your answer, the first digit is your shoe size while the last two digits are your age.
How does this work?
Old chum Brian Walker of Honley, a professional mathematician (among other things) explains:
Let y = shoe size.
Multiply by 5 = 5y.
Add 50 = 5y + 50.
Multiply by 20 = 20 (5y+ 50).
Remove brackets = 100y + 1000.
Ignore for a moment the 100y. Add 1012 to the 1000 which gives you 2012 (the current year). Subtract the date of birth (say1950) 2012 -1950 = 62 . because you are subtracting your date of birth from the current year the result will always be your age.
Now, let us deal with the 100y. Say your shoe size (or y) was 9. Multiplied by 100 multiplied = 900. So 900 + 62 = 962 (9 being the shoe size) and (62 being the age).
See, I knew there was an easy explanation.