Bài 1: Thực hiện phép tính: (Tính nhanh nếu có thể)
a) \(\frac{-1}{24}-\left[\frac{1}{4}-\left(\frac{1}{2}-\frac{7}{8}\right)\right]\)
b) \(\left(\frac{5}{7}-\frac{7}{5}\right)-\left[\frac{1}{2}-\left(-\frac{2}{7}-\frac{1}{10}\right)\right]\)
c) \(\left(-\frac{1}{2}\right)-\left(-\frac{3}{5}\right)+\left(-\frac{1}{9}\right)+\frac{1}{17}-\left(-\frac{2}{7}\right)+\frac{4}{35}-\frac{7}{18}\)
Mọi người ơi, giúp mk với!!!
a) \(\frac{-1}{24}-\left[\frac{1}{4}-\left(\frac{1}{2}-\frac{7}{8}\right)\right]\)
= \(\frac{-1}{24}-\left[\frac{6}{24}-\left(\frac{12}{24}-\frac{21}{24}\right)\right]\)
= \(\frac{-1}{24}-\left[\frac{6}{24}-\frac{-9}{24}\right]\)
= \(\frac{-1}{24}-\frac{15}{24}\)
= \(\frac{-16}{24}\) = \(\frac{-2}{3}\)
b) \(\left(\frac{5}{7}-\frac{7}{5}\right)-\left[\frac{1}{2}-\left(-\frac{2}{7}-\frac{1}{10}\right)\right]\)
= \(\left(\frac{50}{70}-\frac{98}{70}\right)-\left[\frac{35}{70}-\left(-\frac{20}{70}-\frac{7}{70}\right)\right]\)
= \(\frac{-48}{70}-\left[\frac{35}{70}-\left(-\frac{20}{70}-\frac{7}{70}\right)\right]\)
= \(\frac{-48}{70}-\left[\frac{35}{70}-\frac{-27}{70}\right]\)
= \(\frac{-48}{70}-\frac{62}{70}\)
= \(\frac{-110}{70}=\frac{-11}{7}\)
c) \(\left(-\frac{1}{2}\right)-\left(-\frac{3}{5}\right)+\left(-\frac{1}{9}\right)+\frac{1}{17}-\left(-\frac{2}{7}\right)+\frac{4}{35}-\frac{7}{18}\)
= \(\frac{-1}{2}+\frac{3}{5}+\frac{-1}{9}+\frac{1}{17}+\frac{2}{7}+\frac{4}{35}-\frac{7}{18}\)
= \(\left(\frac{-1}{2}+\frac{-1}{9}-\frac{7}{18}\right)+\left(\frac{3}{5}+\frac{2}{7}+\frac{4}{35}\right)+\frac{1}{17}\)
= \(\left(\frac{-9}{18}+\frac{-2}{18}-\frac{7}{18}\right)+\left(\frac{21}{35}+\frac{10}{35}+\frac{4}{35}\right)+\frac{1}{17}\)
= \(-1+1+\frac{1}{17}\)
= \(0+\frac{1}{17}=\frac{1}{17}\)
CHÚC BẠN HỌC TỐT (^_^) !!!!!!!!!!
