Question : What is the value of S $=\frac{1}{1×3×5}+\frac{1}{1×4}+\frac{1}{3×5×7}+\frac{1}{4×7}+\frac{1}{5×7×9}+\frac{1}{7×10}+....$ Up to 20 terms, then what is the value of S?

Question : The value of $4 \div 12$ of $[3 \div 4$ of $\{(4-2) \times 6 \div 2\}]-2 \times 6 \div 8+3$ is:

Question : What is the value of $\frac{3}{2} \div \frac{1}{7} \times[(\frac{1}{2} - \frac{1}{3}) \div \frac{1}{42}]?$

Question : The value of $\frac{2}{3}-\frac{5}{6} \times \frac{4}{5} \div \frac{4}{3}+\frac{1}{2}$ is:

Question : The value of $\left(2 \frac{6}{7}\right.$ of $\left.4 \frac{1}{5} \div \frac{2}{3}\right) \times 5 \frac{1}{9} \div\left(\frac{3}{4} \times 2 \frac{2}{3}\right.$ of $\left.\frac{1}{2} \div \frac{1}{4}\right)$ is: