Choose Table - Insert Table, and insert a table with one column and more than one row into a text document.
Type a number in each cell of the column, but leave the last cell in the column empty.
Place the cursor in the last cell of the column, and then click the Sum icon on the Table bar.
The Formula bar appears with the entry "=sum".
Office inserts a formula for calculating the sum of the values in the current column.
The sum of the values in the current column is entered in the cell.
If you enter a different number anywhere in the column, the sum is updated as soon as you click in the last column cell.
Similarly, you can also quickly calculate the sum of a row of numbers.