Twenty-one times a positive number is less than its square by $100$. The value of the positive number is:

What is the difference between the largest and the smallest fractions among $\frac{5}{8}, \frac{21}{35}, \frac{9}{16}$,and $\frac{6}{7}$?

If $2p + \frac{1}{p} = 4$,then the value of $p^{3} + \frac{1}{8p^{3}}$ 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

The value of $\frac{3}{1^{2} \cdot 2^{2}}+\frac{5}{2^{2} \cdot 3^{2}}+\frac{7}{3^{2} \cdot 4^{2}}+\frac{9}{4^{2} \cdot 5^{2}}+\frac{11}{5^{2} \cdot 6^{2}}+\frac{13}{6^{2} \cdot 7^{2}}+\frac{15}{7^{2} \cdot 8^{2}}+\frac{17}{8^{2} \cdot 9^{2}}+\frac{19}{9^{2} \cdot 10^{2}}$ is

$\frac{1}{8}$ of $\frac{2}{3}$ of $\frac{3}{5}$ of $1715 = ?$