Bài 1 :
a,\(\dfrac{2}{3}\)+5\(\dfrac{3}{7}\):2 +\(\dfrac{9}{49}\).(-7)+\(\dfrac{1}{12}\).(-2)4
= \(\dfrac{2}{3}\)+\(\dfrac{19}{7}\)-\(\dfrac{9}{7}\)+ \(\dfrac{4}{3}\)
=(\(\dfrac{2}{3}\)+\(\dfrac{4}{3}\))+(\(\dfrac{19}{7}\)-\(\dfrac{9}{7}\))
= 2 + \(\dfrac{10}{7}\)
=\(\dfrac{24}{7}\)
b, 2\(\dfrac{3}{4}\).(0,4)-1\(\dfrac{3}{5}\).2,75+(-1,2) :\(\dfrac{4}{11}\)
=\(\dfrac{11}{10}\)-\(\dfrac{22}{5}\)-\(\dfrac{33}{10}\)
= \(\dfrac{-33}{5}\)( em tự quy đồng mẫu ra , mẫu chung là 10 )
c,(2\(\dfrac{1}{3}\) +3\(\dfrac{1}{2}\)):(-4\(\dfrac{1}{6}\)+1\(\dfrac{3}{7}\))+7\(\dfrac{1}{2}\)
= \(\dfrac{35}{6}\): (-\(\dfrac{115}{42}\)) +\(\dfrac{15}{2}\)
=\(\dfrac{247}{46}\)
d,\(\dfrac{2}{3}\)+\(\dfrac{-5}{12}\)
= \(\dfrac{8}{12}\)+\(\dfrac{-5}{12}\)
= \(\dfrac{3}{12}\)= \(\dfrac{1}{4}\)
e,\(\dfrac{-2}{9}\)-\(\dfrac{7}{12}\)=\(\dfrac{-29}{36}\)
f,\(\dfrac{-2}{3}\).\(\dfrac{-9}{12}\)=\(\dfrac{-2.\left(-9\right)}{3.12}\)=\(\dfrac{1}{2}\)
Để tối , anh làm tiếp Nguyễn Phương Linh , bây h có việc bận rồi
