if they knew mathematics, they would count their profits from farming, their profits from other ways to farm(using machines, oxes, plant plants with no fertelizers added, or 'natrual' and sell them at a higher price, etc.) and compare them to figure out the best way to farm in that area, determing from prices of tools the farmer would need from accomplishing this kind of job. the farmer would get to live a better life from farming, and the farmer would, hopefully, expand the agriculture areas, and help the society by providing more food. also, the farmer wuold get more profits.
