Write the set $\left\{\frac{1}{2}, \frac{2}{3}, \frac{3}{4}, \frac{4}{5}, \frac{5}{6}, \frac{6}{7}\right\}$ in the set-builder form.
Which of the following are examples of the null set
Set of odd natural numbers divisible by $2$
Assume that $P(A)=P(B) .$ Show that $A=B$.
Which of the following is a true statement
If $Q = \left\{ {x:x = {1 \over y},\,{\rm{where \,\,}}y \in N} \right\}$, then