Rational Number...

Which property is being used in the following 

The number with which when $$82$$ is multiplied product remains the same.

If $$4\div 5= a$$ and $$5\div 4= b$$, then which of the following is true?

Out of the following, identify which option states commutative property.

Select the appropriate property:
$$a\times b(c)=a \times(c) b$$

Rational numbers are closed under ..........

Given that, $$\dfrac {-15}{2} \times \dfrac {12}{5} = \dfrac {12}{5} \times \dfrac {-15}{2}$$
This is the best example for

For any rational number, multiplicative identity is 

Find the missing value: $$\dfrac {-5}{9} \times \dfrac {6}{-1} = ..... \times \dfrac {-5}{9}$$

Which of the following statements is incorrect, if $$a, b, c$$ and $$d$$ are any rational numbers?