How to calculate Number of the week in the year

In the following example, as you can see in the photo, Number of the week in the year can be identified by the ISOWEEKNUM function.

=ISOWEEKNUM("01/02/1900")----->>>>answer is  1
=ISOWEEKNUM("1-Jan-2020")----->>>>answer is  1
=ISOWEEKNUM("2-Jul-2020")----->>>>answer is  27
=ISOWEEKNUM("3-Sep-2021")----->>>>answer is  35
=ISOWEEKNUM("4-Apr-2022")----->>>>answer is  14

ISOWEEKNUM function

The ISOWEEKNUM function is one of the Date & Time functions of Excel.

It returns the ISO week number in the year for a given date.

ISOWEEKNUM arguments 

=ISOWEEKNUM("Date")----->>>>Number

This function has just 1 Argument:

The argument of ISOWEEKNUM function is date.

The argument of ISOWEEKNUM function is required and not optional.