Sarah Garland:

Every Saturday morning at 10 a.m., Jason Zimba begins a math tutoring session for his two young daughters with the same ritual. His youngest, Claire, 4, draws on a worksheet while his oldest, Abigail, 7, pulls math problems written on strips of paper out of an old Kleenex box, decorated like a piggy bank with a pink snout on one end and a curly-cue tail on the other, and adds the numbers as fast as she can. If she gets the answer “lickety-split,” as her dad says, she can check them off. If she doesn’t, the problem goes back in the box, to try the following week.

Zimba began the Saturday lessons to make up for what he felt was subpar math instruction at Abigail’s public elementary school in Manhattan after it switched to the Common Core, a set of controversial new math and English standards adopted by most states in 2010. The standards have been in place in many districts for three years, but most textbooks, curriculum and teacher training have yet to catch up to the Common Core’s grand vision. The math standards, in particular, have caused outrage across the country as parents have grappled with confusing homework and garbled word problems labeled Common Core. Several states are currently reconsidering the standards in response to the growing backlash.

But Zimba, a mathematician by training, is not just any disgruntled parent. He’s one of the guys who wrote the Common Core.

“I would be sleeping in if I weren’t frustrated,” Zimba says of his Saturday morning lessons, which he teaches in his pajamas. Instead, four years after signing off on the final draft of the standards, he spends his weekends trying to make up for the lackluster curriculum at his daughters’ school and his weekdays trying to make up for the lackluster curriculum and teaching at schools around the country that are struggling to shift to the Common Core.