$$\frac{7}{\frac{6}{\frac{5}{\frac{4}{\frac{3}{\frac{2}{1}}}}}}=\frac{7}{\frac{6}{\frac{5}{\frac{4}{\frac{3}{2}}}}}=\frac{7}{\frac{6}{\frac{5}{\frac{4\cdot 2}{\frac{3}{1}}}}}=\frac{7}{\frac{6}{\frac{5\cdot 3}{4\cdot 2}}}=\frac{7\cdot 5\cdot 3}{6\cdot4\cdot2}$$