31/6 - ( 3/5 + 1/3 + 7/5 )= (31/6-1/3)-(3/5+7/5)=29/6-2=17/6[ 1 - ( 1/4 - 0.1 ÷ 2 ) ] × 5/13=[1-1/5]×5/13=4/5×5/13=4/1324 × ( 3/8 + 2/3 - 5/6 )=24×(3/8-1/6)=24×5/24=5