I hate Google Docs’s spreadsheet app, ‘Sheets’. It’s a lackluster application compared to anything even remotely recent. Its only selling point is the current IT industry’s addiction to simultaneous editing.
I work more with Sales and Finance than I used to, and I find myself referring to things like Fiscal Calendars, which have some relation to Gregorian calendars apparently, and Calendar Weeks, which do not.
In the fine open source program LibreOffice Calc (and presumably Microsoft Excel) there’s a handy function for this, called WEEKNUM. In Google’s spreadsheet, you need to first parse a date, and then slice it.
I googled this from somewhere, and wound up with the following:
= MID(TEXT(A3,"yyww"), 3, 2)
Where A3 is a date.
Seriously, it sucks.