Wednesday, February 07, 2007

Number Magic

Tell a person to think of their birthday...and that you are going to guess it.

Step 1) Have them take the month number from their birthday: January = 1, Feb = 2 etc.
Step 2) Multiply that by 5
Step 3) Then add 6
Step 4) Then multiply that total by four
Step 5) Then add 9
Step 6) Then multiply this total by 5 once again
Step 7) Finally, have them add to that total the day they were born on. If they were born on the 18th, they add 18, etc.

Have them give you the total. In your head, subtract 165, and you will have the month and day they were born on!

1 comment:

Anonymous said...

Hardly magic :P

= 5(4(5m + 6) + 9) + d - 165
= 20(5m + 6) + 45 + d - 165
= 100m + 120 + 45 + d - 165
= 100m + 165 + d - 165
= 100m + d

So all you are doing in essence is multiplying their birth month (m) by 100 and adding the day (d) ... No magic involved. ¬_¬