[ilovemyglo]

Okay, I figured this out the other day-
all the numbers in the teens turn into 9
all the numbers in the 20's turn into the same number- 18
All the numbers in the 30's turn into 27
All the numbers in the 40's turn into 36
All the numbers in the 50's turn into 45
ETC ETC ETC

The reason for this is because the first digit stays the same, while you increase the second digit, therefore when add together they subtract to the same number
For example
23 and 25
2+3=5 23-5= 18
2+5=7 25-7=18

See-
The symbols change everytime and but is the same symbol everytime for all the numbers divisible by 9.