1. Activity Tools: use a calculator, or scratch paper and pencil
Activity Tools: use a calculator, or scratch paper and pencil. Toes and fingers are permitted.
Write the number of the month you were born.
Multiply that by four.
Now, add unlucky “13” (that’s both hands and 3 toes)
Multiply this number by twenty-five.
Subtract two hundred.
Add your birth date (day of the month)

2. Double that.
Subtract 40 from the number.
Multiply by 50.
Now, (whew!), to this add the last 2 digits of your birth year (the truth!)
Think of an integer between 10,499 and 10, 501 and subtract it from your number.
Gottcha! It’s your birthday!
If the answer is wrong, there are two possibilities: You lied or your math is just bad! Try it again.