found this on tumblr:
I'm here to tell you how to find your canon patron troll!
John Egbert was born April 13th, which actually makes him an Aries. But Aradia isn't his patron troll, it's Vriska.
April is the 4th month of the year, thus making his birthday 4-13 in those number date things.
Then, you smoosh all the numbers together, and create the number we all know and love! 413! Now put addition signs between each of the numbers. 4+1+3= 8. WOOOAHHH. Who's the 8th sign in the Zodiac? VRISKA. Woah man!
Her birthday is December 1st. Which is 12-1. And together 121. 1+2+1= 4. Who's the fourth sign in the Zodiac? Cancer!! Thus Jade's patron troll is Karkat.
December 3rd. 12-3. 123. 1+2+3= 6. Virgo is the sixth sign in the Zodiac. Thus, Kanaya is Rose's patron troll.
December 4th. 12-4. 124. 1+2+4= 7. Libra is the seventh sign in the Zodiac. Thus, Terezi is Dave's patron troll.
Woah man, did I just blow your mind? I hope so.
This also helps me remember all the kid's birthdays.
Anyway, another example. My birthday is November 11, so 11-11, 1111, 1+1+1+1=4. Thus my patron is Karkat.
Another note, you may get an answer OVER 12! Do not fret, the next step is [A] pulling up your calculator and dividing the sum by 12. If the product is 1.5 or less, your patron is Aradia. If it's 1.6 or higher, it's Tavros. (At least, these are guidelines I go by.)
And for your reference:
1 - Aradia
2 - Tavros
3 - Sollux
4 - Karkat
5 - Nepeta
6 - Kanaya
7 - Terezi
8 - Vriska
9 - Equius
10 - Gamzee
11 - Eridan
12 - Feferi
it makes more sense to me to subtract by 12, so you get the same number, technically. for example, someone born on 9-29 would end up getting 20 (9+2+9=20), which is 12+8, so their canon troll would be the 8th troll, Vriska, instead of dividing by 12 and getting 1.666... and ending up Tavros. this just makes more sense to me, but you can do what you want *shrug*