Look at the numbers on this face you won't find thirteen in any place. 1,2,3,4,5,6,7,8,9,10,11,12 what am i ?

Question

If possible fill + or - for o and make this true, if not possible then provide the reasoning...

1 o 1/2 o 1/3 o 1/4 o 1/5 o 1/6 o 1/7 o 1/8 o 1/9 o 1/10 o 1/11 o 1/12 = 0

Answer 1

Answer-- A clock

Answer 2

13th floor of an apartment

Answer 3

aNSWER:
A CLOCK (we cant see the 13th number on a clock at any places)