how to sum. I am getting errors.

You need to make sure that the active cell is just below a column (or to the right of a row) of numbers. If you have numbers in b2:b9, click on cell b10 and then click the SUM button.

The SUM() function sums numbers, but all your numbers except 5.90 are entered as text.  Remove the trailing spaces from the numbers and try again.

You're not doing anything wrong...but...for some reason the formatting in column A is messed up.

I retyped everything into another clean column and the sum function woorked fine.

Just checked the attached spreadsheet. Either remove the spaces after each number, or just re-enter them. Only a16 is registering as a number.  The rest are viewed as text because of the extra space after the number.

I do not understand

Could you send me the edited spreadsheet

what is the correct sum?

Thanks. This sum works.