I know how to do some of these but need help based off of Amazon's 2017 10k			2017
Ratio		Ratio Element	Amazon
Gross Margin Percentage		Gross Margin
		Net Sales
Profit Margin (ROS)		Net Income
		Net Sales
EPS		NI - Preferred Dividends
		# CS outstanding
P/E ratio		Market Price of stock
		EPS
Return on Total Assets		NI + (Interest x (1-tax rate))
		Average Total Assets
Return on common SE		NI - Preferred Dividends
		Average SE - Average Preferred Stock
Book value per common share		SE - Preferred Stock
		# CS
Current ratio		CA
		CL
Acid test ratio		Cash + Marketable Sec + Net AR
		CL
AR turnover		Sales on account
		Ave AR
Average collection period		365
		AR Turnover
Inventory turnover		CGS
		Ave Inventory
Average sale period		365
		Inventory Turnover
AP Turnover Ratio		CGS + EI
		Average AP
Average AP payment in days		365
		AP Turnover Ratio
Times interest earned		EBIT
		Interest Expense
Debt-to-equity ratio		Total Liabilities
		Stockholder's Equity
Debt ratio		Total Liabilities
		Total Assets