What quantities are combined by only addition or subtraction?

Quantities that are combined solely by addition or subtraction are typically scalar quantities, such as distance, mass, and temperature. These quantities can be directly added or subtracted, as they have the same unit of measurement. For example, if you have two distances measured in meters, you can add or subtract them to find a total distance. Additionally, financial values, like income or expenses, are often combined in this way to determine net profit or loss.