$\dfrac{71}{75}$ is :

1. terminating

2. non-terminating

3. periodic decimal

4. not a rational number

Which of the following is terminating:

$\dfrac{13}{85}, \dfrac{51}{405} \text{ and } \dfrac{9}{524}$

1. $\dfrac{13}{85}$

2. $\dfrac{9}{524}$

3. $\dfrac{51}{405}$

4. None

Arrange $-\dfrac{5}{9}, \dfrac{7}{12}, -\dfrac{2}{3} \text{ and } \dfrac{11}{18}$ in the ascending order of their magnitudes.

Also, find the difference between the largest and the smallest of these rational numbers. Express this difference as a decimal fraction correct to one decimal place.

Arrange $\dfrac{5}{8}, -\dfrac{3}{16}, -\dfrac{1}{4} \text{ and } \dfrac{17}{32}$ in the descending order of their magnitudes.

Also, find the sum of the lowest and the largest of these rational numbers. Express the result obtained as a decimal fraction correct to two decimal places.