Here is a puzzle which you can use for entertainment in parties with your friends, and enjoy the magic.
Ask your friend to secretly write any number with any number of digits, but not ending with zero.(Say he writes 89635). Now ask him to add up the all digits and then subtract the total from the original number. (In example, the total of all digits is 8+9+6+3+5 = 31, and then subtract the total from original number i.e. 89635 – 31 = 89604). Now ask him to cross any one digit from this resulting number and tell the remaining number. (In example say he crosses out 6 and tells you the remaining number 8904).
Now you have to do your magic. You did not know what was the number he wrote. What was the total of all its digits and what was the difference. You have to tell the digit he crossed out only by knowing the remaining number he told you.
Can you do it? I know many of you will be able to do it. So what are you waiting for? Post your answer now!