Hi can I please get some help with this accounting question for class please? Thank you.

Madlock, Inc. sells a product with a contribution margin of $40 per unit. Fixed costs are $6,800 per month. How many units must Madlock sell to break even? Begin by showing the formula and then entering the amounts to calculate the units Madlock must sell to break even. (Abbreviation used: CM = contribution margin. Complete all input fields. Enter a "0" for items with a zero value.) + = Required sales in units + 1