Bài 1:
a)\(\dfrac{3}{8}\) +\(\dfrac{-5}{8}\)-\(\dfrac{1}{8}\)
b) \(\dfrac{3}{4}\)-\(\dfrac{-1}{2}\)+\(\dfrac{1}{6}\)
c) \(\dfrac{-4}{10}\)+\(\dfrac{15}{25}\)+\(\dfrac{-2}{15}\)
d) \(\dfrac{-7}{12}\)+\(\dfrac{-4}{30}\)+\(\dfrac{1}{6}\)
Bài 2 Tính...
Đọc tiếp
Bài 1:
a)\(\dfrac{3}{8}\) +\(\dfrac{-5}{8}\)-\(\dfrac{1}{8}\)
b) \(\dfrac{3}{4}\)-\(\dfrac{-1}{2}\)+\(\dfrac{1}{6}\)
c) \(\dfrac{-4}{10}\)+\(\dfrac{15}{25}\)+\(\dfrac{-2}{15}\)
d) \(\dfrac{-7}{12}\)+\(\dfrac{-4}{30}\)+\(\dfrac{1}{6}\)
Bài 2 Tính Nhanh
A= \(\dfrac{5}{11}\)+\(\dfrac{-3}{7}\)+\(\dfrac{6}{11}\)+\(\dfrac{2}{3}\)+\(\dfrac{-4}{7}\)
Bài 1:
\(a,\dfrac{3}{8}+\left(-\dfrac{5}{8}\right)-\dfrac{1}{8}\\ =-\dfrac{2}{8}-\dfrac{1}{8}\\ =-\dfrac{3}{8}\\ b,\dfrac{3}{4}-\left(-\dfrac{1}{2}\right)+\dfrac{1}{6}\\ =\dfrac{9}{12}+\dfrac{6}{12}+\dfrac{2}{12}\\ =\dfrac{17}{12}.\\ c,-\dfrac{4}{10}+\dfrac{15}{25}+\left(-\dfrac{2}{15}\right)\\ =-\dfrac{4}{10}+\dfrac{3}{5}-\dfrac{2}{15}\\ =-\dfrac{12}{30}+\dfrac{18}{30}-\dfrac{4}{30}\\ =\dfrac{1}{15}.\\ d,-\dfrac{7}{12}+\left(-\dfrac{4}{30}\right)+\dfrac{1}{6}\\ =-\dfrac{35}{60}-\dfrac{8}{60}+\dfrac{10}{60}\\ =-\dfrac{7}{12}.\)
Bài 2 :
\(A=\dfrac{5}{11}+\left(-\dfrac{3}{7}\right)+\dfrac{6}{11}+\dfrac{2}{3}+\left(-\dfrac{4}{7}\right)\\ =\left(\dfrac{5}{11}+\dfrac{6}{11}\right)-\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{2}{3}\\ =1-1+\dfrac{2}{3}\\ =\dfrac{2}{3}.\)
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