3/4 + 2/7 + 1/6 = 3/4 - 2/7 - 1/6 = 3/4 ÷ 2/7 ÷ 1/6 = 3/4 × 2/7 × 1/6 =

[tex] \frac{3}{4} + \frac{2}{7} + \frac{1}{6} = \frac{126}{168} + \frac{48}{168} + \frac{28}{168} \\ = \frac{126 + 48 + 28}{168} = \frac{202}{168} = \frac{101}{84} [/tex]
[tex] \frac{126 - 48 - 28}{168} = \frac{50}{168} = \frac{25}{84} [/tex]
[tex] \frac{3}{4} \times \frac{7}{2} = \frac{21}{8} \times \frac{6}{1} = \frac{21}{4} \times \frac{3}{1} = \frac{63}{4} [/tex]
[tex] \frac{3}{4} \times \frac{2}{7} \times \frac{1}{6} = \frac{6}{168} = \frac{1}{28} [/tex]