The product of additive inverse and multiplicative inverse of $\dfrac{-1}{4}$ is

1. 1

2. -1

3. 0

4. $\dfrac{-1}{16}$

The reciprocal of a negative rational number

1. is a positive rational number

2. is a negative rational number

3. can be either a positive or a negative rational number

4. does not exist

Which of the following expressions shows that rational numbers are associative under multiplication?

1. $\dfrac{4}{5} \times \left(\dfrac{-6}{7} \times \dfrac{8}{9}\right) = \left(\dfrac{4}{5} \times \dfrac{-6}{7}\right) \times \dfrac{8}{9}$

2. $\dfrac{4}{5} \times \left(\dfrac{-6}{7} \times \dfrac{8}{9}\right) = \dfrac{4}{5} \times \left(\dfrac{8}{9} \times \dfrac{-6}{7}\right)$

3. $\dfrac{4}{5} \times \left(\dfrac{6}{7} \times \dfrac{8}{9}\right) = \left(\dfrac{8}{9} \times \dfrac{4}{5}\right) \times \dfrac{-6}{7}$

4. $\left(\dfrac{4}{5} \times \dfrac{-6}{7}\right) \times \dfrac{8}{9} = \left(\dfrac{-6}{7} \times \dfrac{4}{5}\right) \times \dfrac{8}{9}$

$\dfrac{-1}{4} \times \left[\dfrac{2}{5} + \left(\dfrac{-5}{6}\right)\right]$ = ?

1. $\left[\dfrac{-1}{4} \times \dfrac{2}{5}\right] + \left[\dfrac{-1}{4} \times \left(\dfrac{-5}{6}\right)\right]$

2. $\left[\dfrac{-1}{4} \times \dfrac{2}{5}\right] - \left(\dfrac{-5}{6}\right)$

3. $\dfrac{2}{5} + \left(\dfrac{-1}{4}\right) \times \left(\dfrac{-5}{6}\right)$

4. $\left[\dfrac{2}{5} + \left(\dfrac{-5}{6}\right)\right] - \dfrac{1}{4}$