Edge Corporation has reported the following results for May 2017: Sales $ 855,000 Cost of goods sold 299,250 Gross margin 555,750 Selling and administrative expenses: Selling 110,000 Administrative 170,000 280,000 Net operating income $ 275,750 Other information: Average selling price per unit: $900 Selling expenses comprised of: fixed selling expenses plus 10% of sales Administrative expenses comprised of: fixed administrative expenses plus $63.00 per unit Using the contribution approach, Edge's contribution margin for the month of May is _______.