Click the cell where you want the result to appear
Type =SUM(A1:A10) to add numbers in a column range
Press Enter
To add specific cells, type =A1+A2+A3
To add a new number to an existing total, use =SUM(A1:A10)+B1
To auto-sum a column, select the cell below the numbers and click AutoSum
Press Enter after AutoSum inserts the formula
Copy the formula down if needed by dragging the fill handle
Use the correct column letter and cell references for your data
Replace A1:A10 with your actual range of cells