Please Help! I've been trying to do this question but keep doing a wrong step somewhere

Fill in the missing amounts in each of the eight case situations below. Each case is independent of the others. (Hint: One way to find the missing amounts would be to prepare a contribution format income statement for each case, enter the known data, and then compute the missing items.) Required: a. Assume that only one product is being sold in each the following four case situations: Case #1 Case #2 Case #3 12,400 Unit sold 18,600 Case #4 7,440 $ 372,000 Sales $ $ 124,000 223,200 148,800 Variable expenses 86,800 62,000 39,680 124,000 Fixed expenses Operating income (loss) Contribution margin per unit $ 9,920 $ 14,880 $ (12,400) $ 10 $ 13 b. Assume that more than one product is being sold in each of the following four case situations: (Enter "Contribution margin ratio" in percent. Round your final answers to the nearest whole dollar amount.) Case #1 Case #2 Case #3 Case #4 Sales $ 524,000 $ 424,000 $ 624,000 436,800 Variable expenses 275,600 106,000 137,200 Fixed expenses Operating income (loss) Average contribution margin (percentage) $ 8,200 $ $ (4,800) 27,200 60% 20%