$9999 + 8888 + 777 + ? = 19700$

If the digit in the unit's place of a two-digit number is halved and the digit in the ten's place is doubled,the number thus obtained is equal to the number obtained by interchanging the digits. Which of the following is definitely true?

Two baskets together have $640$ oranges. If $\frac{1}{5}$ of the oranges in the first basket are taken to the second basket,the number of oranges in both baskets becomes equal. The number of oranges in the first basket is:

$73 \times 18 + 486 = ? + (13)^{2}$

Arranging the following in descending order,we get $\sqrt[3]{4}, \sqrt{2}, \sqrt[6]{3}, \sqrt[4]{5}$.

Which one is the largest among the fractions $\frac{5}{113}, \frac{7}{120}, \frac{13}{145}$ and $\frac{17}{160}$?