What is the value of $4^{3}-3^{2}+6^{2}-5^{2}+8^{2}-7^{2} ?$

$A$ sum of $Rs. 1360$ has been divided among $A, B$ and $C$ such that $A$ gets $\frac{2}{3}$ of what $B$ gets and $B$ gets $\frac{1}{4}$ of what $C$ gets. $B$'s share is (in $Rs.$)

$A$ man has some hens and cows. If the number of heads is $48$ and the number of legs is $140$,then the number of hens is:

$\left[\frac{8(3.75)^{3}+1}{(7.5)^{2}-6.5}\right]$ is equal to

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

What should come in place of the question mark $(?)$ in the following equation?
$30.01^{2} - 19.98^{2} - ? = 21.81^{2}$