The number trick of 1089
You need

The number trick with 1089 has been
around for centuries. To impress
someone with this trick, he or she will
need paper and pencils:
Example 1

Step #1:
Have the person write down any three digits number with decreasing
digits (432 or 875).
Step #2:
Reverse the number you wrote in step #1.
Step #3:
Subtract the number obtained in step #2 from the number you wrote in
step #1
Step #4:
Reverse the number obtained in step #3
Step #5:
Add the numbers found in step #3 and step #4
Example 2

Step #1:
Have the person write down any three digits number with decreasing
digits: 752
Step #2:
Reverse the number you wrote in step #1: 257
Step #3:
Subtract the number obtained in step #2 from the number you wrote in
step #1: 752 - 257 = 495
Step #4:
Reverse the number obtained in step #3: 594
Step #5:
Add the numbers found in step #3 and step #4: 495 + 594 = 1089

This number trick with 1089 works with any
3 digits number as long as you choose a
number with decreasing digits in step #1
So, it does not matter what number the
person choose in step #1, have the person
do the math and pretend you are not
looking. When you call the answer as
1089, the person will be shocked! Cool!

This is very cool and amazing trick. To
impress anyone.

Good luck