-7/30除以(3/3-3/5+3/10)
=-7/30除以(10/10-6/10+3/10)
=-7/30除以(7/10)
=-7/30*10/7
=-10/30
=-1/3
-7/30除以(1/3-3/5+3/10)
=-7/30除以(10/30-18/30+9/30)
=-7/30除以(1/30)
=-7/30*30
=-7
-7/30除以(3/3-3/5+3/10)
=-7/30除以(10/10-6/10+3/10)
=-7/30除以(7/10)
=-7/30*10/7
=-10/30
=-1/3
-7/30除以(1/3-3/5+3/10)
=-7/30除以(10/30-18/30+9/30)
=-7/30除以(1/30)
=-7/30*30
=-7