+1 formula

1. Dream up 2 numbers, one two less than the other, say 2 and 4.
2. 2 x 4 = 8.
3.  In the middle of the two numbers is 3.Throw in another 3. 3 x 3 = 9 
4. 8 + 1 = 9

Try 8 and 10. 8 x 10 = 80. 9 x 9 = 81. 80 + 1 = 81