Matthew pulled together the following annual revenue and cost information for his small business: total variable costs $7,000, total COGS $5,400, total revenues $18,400, total fixed costs $3,600, and total SG&A $5,200. Determine the contribution margin, gross margin, and operating income for Matthew for the year. Contribution margin $enter a dollar amount Gross margin $enter a dollar amount Operating income $enter a dollar amount