For the three rational number a, b and c; which of the following is correct:

1. a ÷ b = b ÷ a
2. a x (b ÷ c) = (a ÷ b) x (a ÷ c)
3. a ÷ (b ÷ c) = (a ÷ b) ÷ (a ÷ c)
4. a ÷ (b ÷ c) ≠ a ÷ b ÷ c

The product of two rational numbers is $-7\dfrac{2}{3}$. If one of them is $3\dfrac{5}{6}$, the other number is:

1. 3
2. -3
3. 2
4. -2

Evaluate:

1 ÷ $\dfrac{1}{3}$

Evaluate:

$3 ÷ \dfrac{3}{5}$