0.6X9.8-2/5X50% =0.6X(10-0.2)-1/5 =6-0.12-0.2 =6-0.32 =5.68 9/16X2/5+3/5÷16/9 =9/16X2/5+3/5X9/16 =9/16X(2/5+3/5) =9/16X1 =9/16