(7/12-1/6)÷3/5-0.25=5/12×5/3-0.25=25/36-1/4=25/36-9/36=16/36=4/9
(7/12一l/6)÷3/5一l/4=(7/|2一2/l2)X5/3一l/4=5/|2X5/3一l/4=25/36一9/36=l6/36=4/9
(7/12-1/6)÷3/5-0.25=5/12÷3/5-0.25=25/36-1/4=4/9