Question

[Trần Thị Đào]

bài 1 : tính

a)\(\frac{-5}{13}-\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)\) b) \(\left(\frac{3}{9}-\frac{9}{18}\right)+\frac{3}{6}-\left(\frac{1}{3}-\frac{1}{2}\right)-\frac{5}{15}\) c) \(\frac{9}{18}+\frac{16}{32}-\frac{12}{46}-\frac{9}{17}\) d) \(\left(\frac{14}{18}+\frac{-16}{27}\right)-\left(\frac{2}{3}-\frac{5}{15}\right)\)

Answer 1

[Bùi Bảo Châu]

a)\(\frac{-5}{13}+\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)=\frac{-5}{13}-\frac{3}{5}-\frac{3}{13}+\frac{4}{10}=\left(\frac{-5}{13}-\frac{3}{13}\right)+\frac{4}{10}-\frac{3}{5}=\frac{-5-3}{13}+\left(\frac{4}{10}-\frac{6}{10}\right)=\frac{-8}{13}+\frac{-2}{10}=\frac{-80}{130}+\frac{-26}{130}=\frac{-106}{130}=\frac{-53}{65}\)

Answer 2

[Trần Thị Đào]

tại sao bạn ra \(\frac{-5}{13}\)