Remember, before subtracting using pencil and paper, times should be expressed in 24-hour format. Before typing the formula, highlight column B. From the menu bar, click on Format and drag to Number. This time select the 24-hour format as shown below. To have the computer calculate the hours of daylight type the formula in the entry bar. Type an equal sign.
All formulas begin with the equal sign.
You will notice in the entry bar D2 now follows the equal sign. Next type a minus sign in the entry bar. Click in cell C2. When you press return the answer should appear in cell A2. Click on Options in the menu bar and drag to Make chart.