How many different elements does a × b have if a has m elements and b has n elements?

mn

Step-by-step explanation:

A set refers to a well-defined collection of items.

For example : Set of natural numbers (N)

Set of rational numbers (Q).

A Cartesian product is a product of two different sets .

such as M= {1,2} and N={3,4}

Then M x N  ={(1,3) , (1,4) , (2,3) , (2,4)}

According to the properties of the Cartesian product of sets, if a set P has 'k' elements and an another set Q has 'r' elements , then the number of different elements in P x Q =kr

Similarly , if A has m elements and B has n elements , then A x B has 'mn' elements.

∴ The number of ifferent elements does A × B have if A has m elements and B has n elements= mn

answer: 7

step-by-step explanation: