4÷7/3+3*3/7 =4×3/7+3×3/7=(4+3)×3/7=7×3/7=312/13÷2/5*1/6 =(12/13*1/6)÷2/5=2/13×5/2=5/133/5÷(3/5-2/5)*3/5=3/5÷1/5×3/5=3×3/5=1.8