1.) 7/18-1/2÷3/4-1/3 =7/18-1/2x4/3-1/3 =7/18-2/3-1/3 =7/18-1= -11/18(2.)1/6+3/4×2/3÷2 =1/6+1/2÷2=1/6+1/4=2/12+3/12=5/12(3.)4/25÷【(2/5+1/3)×9/11】=4/25÷【(6/15+5/15)×9/11】=4/25÷【(11/15)×9/11】=4/25÷(3/5)=4/25x5/3=4/15