1089 is known as the **magic number**. See why:

Choose any number from three distinct digits: for example, 875.

Now write this number backwards and subtract the smallest from the largest:

875 - 578 = 297

Now also invert this result and make the sum:

297 + 792 = **1089** (the magic number)

**Warning:** Before you send us an email saying that it doesn't work with certain numbers, please remember that three digits must be used in the calculation. Example:

574 - 475 = **099****099** + 990 = 1089