Theo em một giời đội thứ hai làm được số công việc nhiều nhất và đội thứ ba làm được khối lượng công việc ít nhất.Vì \(\dfrac{5}{27}\)<\(\dfrac{6}{27}\)<\(\dfrac{9}{27}\) vậy nên \(\dfrac{5}{27}\)<\(\dfrac{2}{9}\)<\(\dfrac{1}{3}\) 

b)Mỗi giờ cả ba đội làm được số phần công việc là:

\(\dfrac{1}{3}\)+\(\dfrac{2}{9}\)+\(\dfrac{5}{27}\)=\(\dfrac{20}{27}\)(công việc)

a) x-\(\dfrac{2}{3}\)=\(\dfrac{-5}{12}\)

x=\(\dfrac{-5}{12}\)+\(\dfrac{2}{3}\)

x=\(\dfrac{3}{12}\)

b)\(\dfrac{8}{5}\):x=\(\dfrac{-2}{3}\)

x=\(\dfrac{8}{5}\):\(\dfrac{\left(-2\right)}{3}\)

x=\(\dfrac{12}{-5}\)

c)1-\(\dfrac{3}{7}\).x=\(\dfrac{-2}{7}\)

\(\dfrac{3}{7}\).x=1-\(\dfrac{\left(-2\right)}{7}\)

\(\dfrac{3}{7}\).x=\(\dfrac{9}{7}\)

x=\(\dfrac{9}{7}\):\(\dfrac{3}{7}\)

x=3

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)

a -\(\dfrac{2}{7}\)+\(\dfrac{2}{7}\):\(\dfrac{3}{5}\)

=\(\dfrac{-2}{7}\)+\(\dfrac{10}{21}\)

=\(\dfrac{4}{21}\)

b) \(\dfrac{-8}{19}\)+ \(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\) +\(\dfrac{27}{19}\)

=[\(\dfrac{\left(-8\right)}{19}\) +\(\dfrac{27}{19}\)]+[\(\dfrac{\left(-4\right)}{21}\)-\(\dfrac{17}{21}\)]

=1+(-1)

=0

c)\(\dfrac{6}{5}\).\(\dfrac{3}{13}\)-\(\dfrac{6}{5}\).\(\dfrac{16}{13}\)

=\(\dfrac{6}{5}\).(\(\dfrac{3}{13}\)-\(\dfrac{16}{13}\))

=\(\dfrac{6}{5}\).(-1)

=\(\dfrac{\left(-6\right)}{5}\)