What are X and Y? 7 8 6 9 5 10 X Y 3 12

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

X=4
Y=11
Because the first number is subtraction 1 for third number and the second number is adding 1 for forth number..

Answer 2

X is 4; Y is 11
Two alternate series
Starting with the first number: 7 6 5 4 3
Starting with the second number: 8 9 10 11 12