1/2+2/3-5/6=7/6-5/6=1/37/10-1/8-3/8=7/10-(1/8+3/8)=7/10-1/2=1/53/7+9/10+4/7=3/7+4/7+9/10=1+9/10=1.92-(3/4+5/6)=2-19/12=5/127/10-(3/7-3/10)=7/10+3/10-3/7=1-3/7=4/75/6+4/9+1/6+5/9=(5/6+1/6)+(4/9+5/9)=1+1=2