Write the following sets in roster form :
$C = \{ x:x{\rm{ }}$ is a two-digit natural number such that sum of its digits is $8\} $
In the following state whether $\mathrm{A = B}$ or not :
$A = \{ x:x$ is a multiple of $10\} ;B = \{ 10,15,20,25,30 \ldots \ldots \} $
The number of elements in the set $\{ (a,\,b):2{a^2} + 3{b^2} = 35,\;a,\,b \in Z\} $, where $Z$ is the set of all integers, is
Let $A=\{a, e, i, o, u\}$ and $B=\{a, i, u\} .$ Show that $A \cup B=A$
Write the following intervals in set-builder form :
$\left[ { - 23,5} \right)$