Tính
----- Nội dung ảnh -----
Bài 13. Tính:
a)
\[
\left( \frac{-5}{7} + \frac{7}{9} + \frac{11}{13} \right) \left( \frac{3}{4} - \frac{3}{4} \right)
\]
\[
\frac{10}{21} + \frac{6}{27} + \frac{22}{39}
\]
\[
\left( \frac{2}{3} \right)
\]
b)
\[
3 + \frac{3}{7} + \frac{3}{11} + \frac{3}{1001}
\]
\[
\frac{9}{9} \frac{9}{11} + 9
\]
Bài 13. Tính:
a)
\[
\left( \frac{-5}{7} + \frac{7}{9} + \frac{11}{13} \right) \left( \frac{3}{4} - \frac{3}{4} \right)
\]
\[
\frac{10}{21} + \frac{6}{27} + \frac{22}{39}
\]
\[
\left( \frac{2}{3} \right)
\]
b)
\[
3 + \frac{3}{7} + \frac{3}{11} + \frac{3}{1001}
\]
\[
\frac{9}{9} \frac{9}{11} + 9
\]