Math Trick 3: The Answer is Always 1089

This is the third part of the Math and Multimedia Math Trick Series.  The first two tricks are multiplying by 11 and squaring numbers ending in 5.

As I have promised, I will teach you more math tricks that will impress your friends. The most exciting part, however, is not actually the trick but why the trick works. In this post, we are going to learn math trick which we will call magic 1089, a trick I learned at

The 1089 Math Trick

Step 1: Think of a 3-digit number where its digits are decreasing.

Step 2: Reverse the order of the digits.

Step 3: Subtract the number in step 2 from the number in step 1.

Step 4: Reverse the order of the difference in step 3.

Step 5: Add the numbers in step 3 and step 4.

The result is 1089.  » Read more