$6.4 - 1.6 \div 0.2 = ?$

What is the value of $111 \frac{1}{2} + 111 \frac{1}{6} + 111 \frac{1}{12} + 111 \frac{1}{20} + 111 \frac{1}{30}$?

If the numbers $\sqrt[3]{9}, \sqrt[4]{20}, \sqrt[6]{25}$ are arranged in ascending order,then the correct arrangement is:

What is the value of $(2.3+1.7)^{2}-(2.3-1.7)^{2} ?$

The value of $3+\frac{1}{\sqrt{3}}+\frac{1}{3+\sqrt{3}}+\frac{1}{\sqrt{3}-3}$ is

The difference between the sum of $1 \frac{3}{4}, 2 \frac{1}{3}, 3 \frac{5}{12}, 5 \frac{1}{5}$ and $2 \frac{1}{6}$ and the nearest whole number is