Working with Excel in an office environment extensively needs you to work with a keyboard. You need to be quick to be productive. Time and motion study proves that making use of keyboard shortcuts reduces the time required to accomplish a task. You must learn the shortcuts for the tasks you use more frequently.
The probability is quite higher that you use the “autosum” option quite frequently. When applied, this deploys the SUM function on a selected cell such that cells above that are added. If there is no value above, the preceding cells in the row are checked and the sum of the values is returned.
This task can be done quickly using a keyboard shortcut. You only need to hold ALT and press + button. And SUM function as described above is implemented on the selected cells. Like Cell A6 was selected and ALT+ is pressed to get the sum of cells above the selected cells.