\(\frac{3}{14}:\frac{1}{28}-\frac{13}{21}:\frac{1}{28}+\frac{29}{42}:\frac{1}{28}-8\)
\(=\left(\frac{3}{14}-\frac{13}{21}+\frac{29}{42}\right):\frac{1}{28}-8\)
\(=\left(\frac{9}{42}-\frac{26}{21}+\frac{29}{42}\right):\frac{1}{28}-8\)
\(=\left(\frac{-17}{42}+\frac{29}{42}\right):\frac{1}{28}-8\)
\(=\frac{12}{42}:\frac{1}{28}-8\)
\(=\frac{2}{7}.28-8\)
\(=\frac{56}{7}-8\)
\(=8-8\)
\(=0\)