\(1-\dfrac{2}{3}=\dfrac{3}{3}-\dfrac{2}{3}=\dfrac{1}{3}\)
\(1+\dfrac{1}{6}=\dfrac{6}{6}+\dfrac{1}{6}=\dfrac{7}{6}\)
\(2+\dfrac{1}{6}=\dfrac{12}{6}+\dfrac{1}{6}=\dfrac{13}{6}\)
1 - 2/3 = 3/3 - 2/3 = 1/3
1 + 1/6 = 6/6 + 1/6 = 7/6
2 + 1/6 = 12/6 + 1/6 = 13/6