I see what you are saying.
Here's the thing, I managed Bs and even As in High School Algebra and Geometry but I still had a VERY shaky background in basic math concepts such as Fractions and Decimals and Percents and even order of operations, etc. That B or A was not actually reflecting my true understanding of the material. I was struggling. It hurt me. By Algebra II I was completely floundering. And in the real world I also struggled with not fully grasping those concepts. I had to work really, really hard to get past those deficits to handle the finances for my dad's business when he passed on. Honestly, I resent the huge gaps in understanding that the public school crippled me with. I had enough exposure to the material and was bright enough I could sort of fake true understanding and pass with decent grades. I did not actually understand critical basic math concepts at a deep enough level to properly "get" what I was doing. Yes, I did actually end up enjoying higher level math classes in Algebra I and Geometry and certainly being able to do higher level math helped with understanding and anchoring to some of the more basic processes but a lot was never mastered and it did affect my functionality as an adult.
If all the parent is going to do is help a child to sort of limp along to get to a point where they can kind of fake understanding well enough to pass with Bs that seems really wasteful and neglectful to me. They are hurting their kid. When I think about this type of scenario, even if the child is getting Bs on math tests I would want the student to actually truly understand the basics, even if there are areas they still struggle as they move into higher level math. There are Bs and there are Bs. A very bright student can sort of fake their way through. That B may not actually reflect 80% mastery/understanding. If the B is showing true understanding/mastery of 80% of the material, o.k. fine. But I would not want to gamble that it does.
I agree. Might as well just teach the kid arithmetic through division, give him an overview of fractions and decimals, teach him to use a calculator to figure a percentage, and call it done. Frankly, this is where *most people's* math skills fall in adulthood anyway. Why bother with the rest?