The company you work for will contribute 12 percent of your gross pay to a 401(k) plan in your name. You can add up to another 10 percent of your gross pay to the same account, but the total contribution (the company's plus yours) cannot exceed $ 10,000. Create a worksheet with the following columns: Gross Pay, Employer Contribution, My Contribution, and Total contribution. Enter a value for your gross pay and create a formula to calculate the company contribution. In a column to the right, enter the numbers 0 to 10. Format them as percentages. Create a list box that uses the percentages and calculates your contribution for the My Contribution column. Total the contributions. Use the combo box to see how much of the gross pay you can contribute to the IRA without exceeding the $10,000 limit.