Return on investments is the amount of money gained from investment in an asset class. For example, if you invest N1m in a business and made N100k profit, your return on investment is 10%.
Return on Investment (ROI) is a good measure for determining an investment especially when compared to another investment. It can also be compared to inflation rate. For example, if a deal as an ROI of 10% and inflation rate is 5% then the deal as an effective ROI of 5%.