Common Core advocates acknowledge parents are frustrated, but blame the problems on botched implementation, insufficient training or poorly written math programs that predate Common Core.
They say schools also need to communicate better.
"The homework can appear ridiculous when it is taken out of context — that's where the biggest problem lies," said Steve O'Connor, a fifth-grade math teacher in Wells, New York. "Parents don't have the context, nor have they been given the means to see the context."
O'Connor has set up a website in an effort to reduce parents' frustration over homework. Other school districts have held workshops for parents to learn alongside their children.
But many parents say they've been on their own, complaining that districts have foisted new math curricula with little explanation.
In Pennsylvania, which signed on to the national Common Core in 2010 but developed its own version, Allison Lienhard said homework sessions with her 10-year-old have ended in tears.
"She gets frustrated because I can't do it the way they are supposed to do it," Lienhard said. "To me, math is numbers, it's concrete, it's black-and-white. I don't understand why you need to bring this conceptual thing into math — at least not at this age."