First, open the Excel2013, select the serial number you want to insert, the following figure, small set to enter the number in the C2, then click C2, enter the function "=row ()-1", row () This function is to obtain the line number meaning;
Second, enter the function directly after clicking Enter jump into the next line, you will find that the function value has automatically become 1;
Third, then click the lower right corner of the C2 cell, when the mouse into a solid cross, pull down, the range according to your actual needs, then release the mouse;
Four, you will find all the cells have been automatically filled with the serial number;
Five, then you can try to delete the whole line in Excel, check your study results.