On simplification of   $$ {(2.664)^2-(2.356)^2\over0.288}$$

The least number, by which 1944 must be multiplied so as to make the result a perfect cube is 

By what least number should 4320 be multiplied so as to obtain a number which is perfect cube? 

Simplify : $$ {(2x)^{2}-(2y)^{2}-(4x)^{2}}$$

The smallest number that must be subtracted from 1000 to make the resulting number a perfect square is 

Given that ( 1² +2²+3²+………..+10²)=385, the value of (2²+4²+6²+……20²) is equal to

Find the value of given equations

$$\left({216\over1} \right) ^{-{2\over3}}÷\left({27\over1} \right) ^{-{4\over3}}=? $$

Direction: what should come in place at question mark(?).

$$ {4\over 7}×{2{4\over 5}÷{2\over 5}=?}$$