Question

If a set contains $m$ elements and $B$ contains $n$ elements, then find the number of elements in $A\times B$.

Answer 1

No of elements in set $A=m$

No of elements in set $B=n$

So, no of elements in $A\times B$ $=m\times n$

Note: $A\times B$ is not equal to $B\times A$ only in case $A=B$ they are equal.