Mua 5 gói kẹo hết 80.000 đồng .Hỏi  mua 3 gói kẹo hết bao nhiêu tiền ?

1.Tính 

        \(a,5\text{x}\dfrac{7}{3}\)                 \(b,\dfrac{13}{4}:7\)

2.Tính

   \(a,\dfrac{3}{7}+\dfrac{2}{5}+\dfrac{3}{4}\)     \(b,\dfrac{9}{7}-\dfrac{5}{11}\text{x}\dfrac{11}{7}\)      \(c,\dfrac{3}{5}\text{x}\dfrac{5}{7}\text{+}\dfrac{4}{7}\)      \(d,\dfrac{7}{9}\text{x}\dfrac{2}{5}:\dfrac{3}{11}\)   e,\(\dfrac{9}{7}+\dfrac{2}{3}-\dfrac{1}{4}\)

                       g,\(\dfrac{4}{9}:\dfrac{3}{5}\text{x}\dfrac{2}{11}\)      h,\(\dfrac{7}{2}-\dfrac{3}{10}:\dfrac{2}{5}\)