1. The problem is about labeling a red line on a histogram in Excel with numbers. 2. To type a number on a red line (or any line) in Excel, you can use a text box or add a data label. 3. First, select the red line by clicking on it. 4. Then, right-click and choose "Add Data Label" if it's a data series line. 5. If it's a drawing line, go to the Insert tab, click "Text Box," then click near the red line and type the number you want. 6. You can drag the text box to position it exactly on the red line. 7. Format the text box font and color as needed to make the number visible. 8. This method allows you to place any number or text on your red line in Excel charts or drawings. Final answer: Use a text box from the Insert menu to type and position numbers on your red line in Excel.