Numbers cell not showing 0?

Please check your formula.

You use "0" that will tell Number to return a TEXT 0

If you want Number to use the numerical value 0 you just use 0 in your formulas.

You also check if the column Start or Finish contains a date / time, I think you should check each row individually.

You calculate data for a row and not the complete column.

You could also use ISDATE to check if a date / time was entered in the Start / Finish cell

Please check also the formula in the second screenshot.

For what do you need the + before DUR2HOURS?

Based on your region the , or the ; will be used to separate the different sections of a formula. If you write one thousand as 1,000.00 then the , is used as your formula separator. If you write one thousand as 1.000,00 then the ; is used as your formula separator.

Hope this will solve your question, please let me know if this worked for you or if something in unclear.

Regards Ralf

I believe the problem is a lot of your "numbers" are text/strings, not actual numbers. Whenever you put quotes around something it turns it into text, like the "0" in your formula. Or if you format a cell/column as text, anything you enter into that cell/column will be text. The blue warning triangles are probably telling you that you are comparing a number to a string. If you had to format the cells/columns to get the "numbers" to align to the right of the cells because they were aligned on the left, that is a sign they are text.