{(7/16-1/4)+15/16}÷1/2 ={3/16+15/16}÷1/2=18/16÷1/2= 9/4=4分之9
{(7/16-1/4)+15/16}÷1/2 ={3/16+15/16}÷1/2=18/16÷1/2= 9/4÷1/2=9/4
{(7/16-4/16)+15/16}÷1/2 ={3/16+15/16}*2=18/16 * 2=9/4