Barnard Manufacturing earned operating income last year as shown in the following income statement:

Sales ............................................................$4,000,000
Cost of goods sold...................................... 2,100,000
Gross margin............................................. $1,900,000
Selling and administrative expense.......... 1,100,000
Operating income........................................ $ 800,000
Less: Income taxes........................... (@ 40%) 320,000
Net income................................................... $ 480,000

At the beginning of the year, the value of operating assets was $2,700,000. At the end of the year, the value of operating assets was $2,300,000.

Required:
Calculate 

(1) Average operating assets, 

(2) Margin, 

(3) Turnover, 

(4) Return on investment.