get rid of blue triangle

Try this instead:

=INT((STRIPDURATION(A2−DATE(YEAR(A2−WEEKDAY(A2−1)+4),1,3))+WEEKDAY(DATE(YEAR(A2−WEEKDAY(A2−1)+4),1,3))+5)/7)

In Dutch:

=INTEGER((VERWIJDER.TIJDSDUUR(A2−DATUM(JAAR(A2−WEEKDAG(A2−1)+4);1;3))+WEEKDAG(DATUM(JAAR(A2−WEEKDAG(A2−1)+4);1;3))+5)/7)

When copy-pasting, be sure to scroll to the right to get the whole formula.

SG

Shouldn't be giving you a warning notice if you're using the WEEKNUM function in the right side cell.

Weeknum accepts a Date and Time value, ignores the time part, and returns a number value.

Unless your formula is more complex than this one, I see no reason for the warning triangle.

Regards,

Barry

To remove the warning triangle, you'll need to fix the issue that is causing it. Click on the triangle to read the message it is a flag for. Without information regarding what it is warning of, it's difficult to offer a solution.

Regards,

Barry