How to count rows/cells after the table is filtered:Excel

Suppose a table has x rows with values. We filter it for certain query and count the elements in  now filtered output. It still returns as the count. How do we count rows/cell in a filtered data?

Let us go through this example:

The COUNTA function returns the value to be 20.

Now if we I filter it for people with only number 1 .

The count is still 20.

Now to count for how many people have  number A we will have to use the subtotal function.

funtion_num is the function we want to use on the 'sub-data' that is the filtered table. Here we will select 3 i.e. COUNTA.

ref: select the data to be counted

So we get our subtotal to be 11.