\(\dfrac{1}{7}+\dfrac{2}{9}+\dfrac{3}{10}+\dfrac{7}{9}+\dfrac{6}{7}+\dfrac{7}{10}\)
\(=\left(\dfrac{1}{7}+\dfrac{6}{7}\right)+\left(\dfrac{2}{9}+\dfrac{7}{9}\right)+\left(\dfrac{3}{10}+\dfrac{7}{10}\right)\)
\(=1+1+1\)
\(=3\)
\(\dfrac{1}{7}\) + \(\dfrac{2}{9}\) + \(\dfrac{3}{10}\) + \(\dfrac{7}{9}\) + \(\dfrac{6}{7}\) + \(\dfrac{7}{10}\)
= ( \(\dfrac{1}{7}\) + \(\dfrac{6}{7}\)) + ( \(\dfrac{2}{9}\) + \(\dfrac{7}{9}\)) + ( \(\dfrac{3}{10}\) + \(\dfrac{7}{10}\))
= 1 + 1 + 1
= 3