If you have a base salary of $500 per month and you get an extra $90 per item sold with a goal of $5000 next month...we would first subtract the known salary of $500 from the $5000. This gives us $4500 we need to make up in sold items. To get this, we divide the $4500 by the $90 to get a total of 50 items we need to sell to reach our goal of $5000.
