The LCM of 315 and 9 is 315
The LCM of 2 and 9 is 18
36
2
18
36 and 3, respectively.
The LCMs of 5 and 9 is 45
12, 24, 36
The lowest common multiple is 36
26
The three LCMs pf 2,3 & 6 are 6, 12 & 18
Good old LCMs! 1/6 = 5/30, 3/10 = 9/30 so the answer is -4/30 ie -2/15