Inventory Turnover Ratio & Days in Inventory

Taking the Business Analytics course on Coursera today (by Duke University) and ran into the concept and formula of Days in Inventory. The instructor briefly mentioned how to estimate Walmart's Days in Inventory using its public financial data: Year-End Inventory/annual Cost of Goods Sold*365. From the course forum I was led to this wikiHow page: https://www.wikihow.com/Calculate-Days-in-Inventory which lays out the process of calculating Inventory Turnover Ratio and then Days in Inventory. That makes it much easier to grasp the whole thing (I think in the course the instructor used Year-End Inventory as Average Inventory).

A lower inventory days measurement means that you are achieving higher inventory turnover and a better return on assets. Calculating inventory days involves determining the cost of goods sold and average inventory in a given period. To calculate the days in inventory, you first must calculate the inventory turnover ratio, which comprises the cost of goods sold and the average inventory. Then, you'll need to divide the number of days in the period by this inventory turnover ratio to determine days in inventory.

Whoo... reminds me of those economics courses I took in college and the "mini MBA" course during MA. Haven't used that part of my brain muscle for a while and feeling good to refresh.