Then they should be flunked. It sucks but parents need to enforce real learning. Schools can't be the sole "responsible" entity here. This is not the instructor's fault and school admin needs to push back. We as a society need to push back otherwise it all falls apart. Not everyone can be a blue collar worker, and most of the BC workers I know tend to be decent at math at least in those items that are part of their work, which they certainly couldn't have picked up if they didn't at least know some basics arithmetic