Hey everybody! I think this might amuse you. Try this algebra trick. You will need a friend to help you.
Formula: n+n+1+n+7+n+8 (take note of this formla)
Tell your friend to pick four dates on a calendar that make a square. eg. 1,2,8,9. Make sure that they don`t tell you which dates they picked.
Then tell them to add their numbers up then make them tell you what the sum of the numbers was.
Subtract 16 from this number. (because the numbers in the formula add up to 16)
Then divide the new number by 4 (because there are 4 n's in the formula)
The number you get now is the first date in their box. Then add 1 and get the second date, add 7 to the first date to get the third date and add 8 (to the first date) to get the 4th date.
Then ask them if the dates you got were the same as theirs. They were, weren`t they?
If they weren`t, you should try again because it worked for everybody in my Maths Class.