Bài 1: Tính hợp lý

a)\(\frac{-3}{4}\)+\(\frac{3}{7}\)+\(\frac{-1}{4}\)+\(\frac{4}{9}\)+\(\frac{4}{7}\) b)\(\frac{-7}{9}.\frac{4}{11}+\frac{-7}{9}.\frac{7}{11}+5\frac{7}{9}\)

c)\(\left(\frac{21}{31}+\frac{2013}{6039}\right)-\left(\frac{44}{53}-\frac{10}{31}\right)-\frac{9}{53}\)

16 tính bằng cách hợp lí 

a) (  \(\frac{1}{4}\)+ \(\frac{-5}{13}\)) + ( \(\frac{2}{11}+\frac{-8}{13}+\frac{3}{4}\))

b) ( \(\frac{21}{31}+\frac{-16}{7}\)) +(  \(\frac{44}{53}\)+ \(\frac{10}{31}\)) +\(\frac{9}{53}\)
c) \(\frac{-5}{7}+\frac{3}{4}+\frac{-1}{5}+\frac{-2}{7}+\frac{1}{4}\)

d) \(\frac{-3}{31}+\frac{-6}{17}+\frac{1}{25}+\frac{-28}{31}+\frac{-11}{17}+\frac{-1}{5}\)

\(a,\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right).\frac{15}{78}\)

\(b,\frac{-7}{21}+\left(1+\frac{1}{3}\right)\) \(c,\frac{2}{15}+\left(\frac{5}{9}+\frac{-6}{9}\right)\)

\(d,\left(\frac{-1}{5}+\frac{3}{12}\right)+\frac{-3}{4}\)

\(e,\frac{4}{20}+\frac{16}{42}+\frac{6}{15}+\frac{-3}{5}+\frac{2}{21}+\frac{-10}{21}+\frac{3}{20}\)

1.Tính nhanh :

a)M=\(\frac{17}{5}.\frac{-31}{125}.\frac{1}{2}.\frac{10}{17}.\frac{-1}{2^3}\)

b)N=\(\frac{1}{7}.\frac{5}{9}+\frac{5}{9}.\frac{2}{7}+\frac{5}{9}.\frac{1}{7}+\frac{5}{9}.\frac{3}{7}\)

c)P=\(\frac{6}{7}.\frac{8}{13}+\frac{6}{9}.\frac{9}{7}-\frac{3}{13}.\frac{6}{7}\)

d)Q=\(\left(\frac{-9}{25}\right)\frac{53}{3}-\left(\frac{-5}{3}\right)^2.\frac{22}{3}\)

2. Tính :

a)P=\(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{1000}\right)\)

b)Q=\(\frac{7}{3.5}+\frac{7}{5.7}+\frac{7}{7.9}+...+\frac{7}{37.39}\)

1 tính 

a \(\left(\frac{9}{14}-\frac{9}{21}\right):\left(\frac{4}{5}+\frac{5}{6}\right)\)

b \(\frac{7}{10}-\frac{-3}{4}+\frac{-5}{6}-\frac{1}{5}+\frac{-2}{3}\)

c \(\left(-2\right)^2.\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)

d \(-\frac{1}{7}.\left(9\frac{1}{2}-0,75\right):\frac{2}{7}+0,625:1\frac{2}{3}\)