Which fraction among $\frac{2}{3}$,$\frac{4}{5}$,and $\frac{7}{11}$ is the largest?

The greatest number among $\sqrt{5}, \sqrt[3]{4}, \sqrt[5]{2}, \sqrt[7]{3}$ is

$1002 \div 49 \times 99 - 1299 = ?$

$8000 \div 16 - 200 = ? \times 6$

The sum of three numbers is $2$. The $1^{\text{st}}$ number is $\frac{1}{2}$ times the $2^{\text{nd}}$ number and the $3^{\text{rd}}$ number is $\frac{1}{4}$ times the $2^{\text{nd}}$ number. The $2^{\text{nd}}$ number is

Which number should replace both the $*$s in $\left(\frac{*}{21}\right) \times \left(\frac{*}{189}\right) = 1$?