[tex] \sqrt[20]{5} \times \sqrt[5]{5} \div \sqrt[4]{5} [/tex]

5^(1/5)=5^(4/20);

5^(1/20) * 5^(4/20) = 5^(5/20)=5^(1/4);

5^(1/4) / 5^(1/4)=1;