All the cells of negative numbers will become red, while the positive numbers will remain the same. You can create your own custom format in Excel to highlight negative numbers. Select the range ...

Select whether to display negative numbers preceded by a minus sign; in parentheses, either with black or red type; or in red type with no minus sign. Excel displays a preview to help you ...

You can subtract numbers in Microsoft Excel in a few different ways, depending on your data and formatting.