wow this thing is crazy

[F L E S H]

It's simple really. Take any 2 digit number, let's say 48. Do the equation, and you get 48 - (4 + 8) = 36. Let's try it again, with a different number, say 79. 79 - (7 + 9) = 63. What do 36 and 63 have in common? they're both multiples of 9. In fact, any time you do the equation, you'll automatically get a multiple of 9. Now look at the chart and look at all the multiples of 9, like 9, 18, 27, 36, 45, etc. Notice something?

[givemesomeweed]

it only worked once for me

[Omun]

If it didn't work your not adding and subtracting correctly because you should always come up with a multiple of 9 like ermitonto said and all the multiples of nine (the only possible answers) all are assigned the same symbol.