\(a,\dfrac{34}{15}+\dfrac{40}{17}-\dfrac{4}{15}-\dfrac{6}{17}=\left(\dfrac{34}{15}-\dfrac{4}{15}\right)+\left(\dfrac{40}{17}-\dfrac{6}{17}\right)=\dfrac{30}{15}+\dfrac{34}{17}=2+2=4\\ b,\dfrac{9}{10}+\dfrac{7}{9}+\dfrac{5}{8}+\dfrac{3}{7}+\dfrac{3}{5}+\dfrac{2}{5}+\dfrac{4}{7}+\dfrac{3}{8}+\dfrac{2}{9}+\dfrac{1}{10}=\left(\dfrac{9}{10}+\dfrac{1}{10}\right)+\left(\dfrac{7}{9}+\dfrac{2}{9}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)=\dfrac{10}{10}+\dfrac{9}{9}+\dfrac{8}{8}+\dfrac{7}{7}+\dfrac{5}{5}=1+1+1+1+1=5\)
a.\(=\dfrac{34}{15}-\dfrac{4}{15}+\dfrac{40}{17}-\dfrac{6}{17}=\dfrac{34-4}{15}+\dfrac{40-6}{17}=2+2=4\)
b.\(=\dfrac{9}{10}+\dfrac{1}{10}+\dfrac{7}{9}+\dfrac{2}{9}+\dfrac{5}{8}+\dfrac{3}{8}+\dfrac{3}{7}+\dfrac{4}{7}+\dfrac{3}{5}+\dfrac{2}{5}\)
\(=1+1+1+1+1=5\)
\(a,=\left(\dfrac{34}{15}-\dfrac{4}{15}\right)+\left(\dfrac{40}{17}-\dfrac{6}{17}\right)\\ =2+2=4\\ b,=\left(\dfrac{9}{10}+\dfrac{1}{10}\right)+\left(\dfrac{7}{9}+\dfrac{2}{9}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\\ =1+1+1+1+1=5\)
