An operating income is divided by revenues to calculate return on sales. Return on sales (ROS) is a measure of how efficiently a company turns sales into profits. ROS is calculated by dividing operating profit by net sales. ROS is only useful when comparing companies in the same line of business and of roughly the same size.
Sum of all resources used to generate income is classified as
Sum of all resources used to generate income is classified as investment. An investment is a monetary asset purchased with the idea that the asset will provide income in the future or will later be sold at a higher price for a profit.