looking at your friend, ask him/her to write down any number that is at
least four digits long.
Then ask your friend to add up the digits.
1+3+5+7+9 = 25
Now subtract this answer (25) from the first number.
13579 - 25 = 13554
Ask your friend to cross
out one digit from the answer. (You can not cross out a zero)
Now ask our friend to slowly read out the digits that are left.
You now magically say : "The missing number is three."
How to do the
missing number math trick
This is a power of 9 trick.
Once your friend crosses out a
digit and reads out the digits that are
left, you simply add
Example : 1+5+5+4 = 15
You now add on to your answer to get the next number
that divides by nine!
The next number to divide by 9 after 15 is 18.
Therefore you need to add on three.
This is the number that was crossed out!