=3/4*34/3-89/10*11/89=34/4-11/10=8 1/2-1 1/10=8 5/10-1 1/10=7 2/5
=91/6*5/91+13/100*92/13=5/6+23/25=125/150+138/150=263/150=1 113/150
=489/5*23/489-1/47*94/3=4 3/5-2/3=3 24/15-10/15=3 14/15
=470/7*3/5+167/5*19/167=40 2/7+3 4/7=40 10/35+3 28/35=44 3/35