It's a truly humbling moment when your child asks you to help diagram a sentence or solve a grade-level math problem and you, a functioning adult with a diploma and years of experience, draw a complete blank. Anyone with school-aged children can probably relate. And as many schools start the year with virtual learning, parents are trying to summon even more of that long-forgotten knowledge. Helping your child navigate Zoom tech support can be daunting. So can balancing work and household duties with making sure your children are engaged and learning. But the single biggest challenge, many parents say, are the math topics taught through Common Core -- a standardized teaching method rolled out in 2010......