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.
We see that each member in the given set has the numerator one less than the denominator. Also, the numerator begin from $1$ and do not exceed $6 .$ Hence, in the set-builder form the given set is
$\left\{ {x:x = \frac{n}{{n + 1}},} \right.$ where $n$ is a natural number and $\left. {1 \le n \le 6} \right\}$
Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?
Write the following intervals in set-builder form :
$\left[ { - 23,5} \right)$
Write the solution set of the equation ${x^2} + x - 2 = 0$ in roster form.
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{\varnothing\} \subset A$
Which of the following is a true statement