(-1/126)/(1/9-2/7+2/3-1/14)
=-1/126*1/(1/9-4/14+6/9-1/14)
=-1/126*1/(7/9-5/14)
=-1/126*1/(98/126-45/126)
=-1/126*1/(53/126)
=-1/126*126/53
=-1/53