How do I add up cells?

Hi Helen, Thank you for your post, welcome to the forum, I hope you are enjoying your Excel Intro course, in answer to your question, adding cells is one of the most common functions in Excel, there are a number of ways of adding values depending on the values and cells you wish to add;
If your cells contain values and you wish to add them and have a resulting value which will reflect any changes to the contents of the cells follow these steps;
1st Example; values in cells A1 and B1 total required in cell C1:
formula will be, in cell C1 type =A1+B1
2nd Example; same scenario as above but using the SUM function, formula will be, in cell C1 type =SUM(A1,B1)
3rd Example; if you have a number of cells which are adjoining (a range of cells) ie A1 through to A10 and you wish to add them all up with the answer in cell A11;
formula will be, in cell A11 type =SUM(A1:A10) the colon (:) informs Excel to use the range of all the cells from A1 through to A10. I hope that has helped, if so please click the Resolved link, best regards Pete