Green Triangle in top left corner

[Philosophaie]

What is the Green Triangle in top left corner for. Does it mean it is not formatted correctly?

 

[Steve Saunders]

It means that there is a potential problem (note the word potential) with a formula. You may want to check for:

Invalid data types
Inconsistent formula
Leading zeros (Number stored as text)

Usually it appears for me when there is an inconsistent formula.

 

[MARK858]

It'll tell you what it thinks the issue is if you click on the triangle (it'll also give you the option to ignore the error which will remove the triangle, if you have more than 1 cell in a continuous range, then select the range from the top left cell to the bottom right cell, click on the triangle on the first cell, click ignore error and it will remove all the triangles in the range)