Explain the Counting Principle in maths?

The fundamental counting principle is used when you want to calculate the total number of possible outcomes (or combinations) of an experiment.

The fundamental counting principle states that:

if you have more than one set of elements (such as a number, a letter, an animal, a city, etc.), and you want to know the different combinations you can make when you select one element from each set,
you simply find the product of the total number of elements from each set.

For example, how many ways can a license plate number be written? Suppose a given license plate has 7 characters - 4 letters and 3 numbers:

There are 26 letters in the English alphabet (a, b, c,...,y, z) and 10 numbers that could be used (0, 1, 2,...,8, 9).

The total number of possible outcomes (combinations) is

(26 x 26 x 26 x 26 x 10 x 10 x 10) =

(26⁴ x 10³) = 456,976,000