Question

[lê thị ngọc anh]

tính :

2/7+-3/8+11/7+1/3+1/7+5/-8

Answer 1

[Hoàng Ninh]

\(\frac{2}{7}+\frac{-3}{8}+\frac{11}{7}+\frac{1}{3}+\frac{1}{7}+\frac{5}{-8}\)

= \(\frac{2}{7}+\frac{-3}{8}+\frac{11}{7}+\frac{1}{3}+\frac{1}{7}+\frac{-5}{8}\)

= \(\left(\frac{2}{7}+\frac{11}{7}\right)+\left(\frac{-3}{8}+\frac{-5}{8}\right)+\left(\frac{1}{7}+\frac{1}{3}\right)\)

= \(\frac{13}{7}+-1+\frac{10}{21}\)

= \(\frac{39}{21}+\frac{-21}{21}+\frac{10}{21}\)

= \(\frac{28}{21}\)

= \(\frac{4}{3}\)

Answer 2

[Hoàng Đình Đại]

\(\frac{2}{7}+\frac{-3}{8}+\frac{11}{7}+\frac{1}{3}+\frac{1}{7}+\frac{-5}{8}\)

\(\Rightarrow\left(\frac{2}{7}+\frac{11}{7}+\frac{1}{7}\right)+\left(\frac{-3}{8}+\frac{-5}{8}\right)+\frac{1}{3}\)

\(\Rightarrow\frac{14}{7}+\frac{-8}{8}+\frac{1}{3}\)

\(\Rightarrow2+\left(-1\right)+\frac{1}{3}\)

\(\Rightarrow1+\frac{1}{3}\)

\(\Rightarrow\frac{4}{3}\)

chúc bạn học giỏi !    ^_^