There are generally two methods for (1) summation, one is to directly input the summation formula, and the other is to directly input the calculation formula. Let's talk about the input method of the summation formula first. Enter "=sum ()" in the specified cell, then stop the cursor in the bracket, and then select the number that requires sum. The selected cells will be displayed in parentheses, and then click Enter to complete the summation process.
(2) Or choose the sum formula in the toolbar to input directly, first stop the cursor in the cell you specify, input and click the formula in the toolbar, select sum, adjust the blue box to select the number you want to sum, and then click Enter.
(3) Another method is to directly input the calculation formula. For example, if I add the numbers of three cells, D 1, D2 and D3, first stop the cursor on the cell you specify, enter the equal sign and the address of the selected cell, =D 1+D2+D3, and the system will automatically recognize the number you entered in the cell address, and then click Enter.