You can't do subtraction in the form of a spreadsheet. According to homework help official website, the calculation algorithm of the elapsed time of the second volume of the second grade clocks and watches is the end time minus the start time, and the end time equals the elapsed time. The elapsed time of the questions after 24 o'clock is equal to 24 o'clock MINUS the start time and end time, which cannot be subtracted by the electronic form.