\(\frac{2}{3}+\frac{1}{4}+\frac{1}{12}=\frac{8}{12}+\frac{3}{12}+\frac{1}{12}=\frac{12}{12}=1\)
\(\frac{4}{5}-\frac{1}{2}-\frac{1}{4}=\frac{16}{20}-\frac{10}{20}-\frac{5}{20}=\frac{1}{20}\)
\(\frac{6}{7}\times\frac{5}{8}\times\frac{14}{15}=\frac{6\times5\times14}{7\times8\times15}=\frac{2\times3\times5\times2\times7}{7\times2\times2\times2\times5\times3}=\frac{1}{2}\)
\(\frac{12}{35}-\frac{4}{7}\times\frac{1}{6}=\frac{12}{35}-\frac{4}{42}=\frac{26}{105}\)