Why is this Common Core math problem so hard? asks Hechinger’s Sarah Garland.
A frustrated father posted a subtraction problem from his second-grade son’s math quiz on Facebook. Students are supposed to write a letter to “Jack” telling him what he did right and wrong in using a number line to subtract 316 from 427.
The father, Jeff Severt, who has a bachelor’s in engineering, told “Jack” he was stumped by the problem himself. “In the real world, simplification is valued over complication,” Severt wrote.
Severt’s son is on the autism spectrum and has problems with attention and language, so this kind of problem is especially difficult, the father said.
Jason Zimba and William McCallum, lead writers of Common Core math standards, blamed a poorly written curriculum for the problem, writes Garland. Common Core requires fluency in the simple skills of adding and subtracting, just what the critics want, said McCallum.
The question appears to be aiming for several Common Core math standards for second grade, writes Garland.
Students are supposed to understand place value and to add and subtract using “models or drawings and strategies based on place value … and relate the strategy to a written method.” They must “explain why addition and subtraction strategies work, using place value and the properties of operations.” The standards call for using number lines.
“Being able to explain how you arrived at an answer – not just memorizing a formula – is also one of the standards’ key goals for students,” she writes.
In the math problem encountered by Severt’s son, “What the kid did is kept subtracting 10. So they didn’t go down to the smaller unit. And whoever is looking at the problem is supposed to see that the student was confused about place value,” said McCallum. “A discussion in the classroom is supposed to talk about how 10 is 10 times bigger than one, and 100 is 10 times bigger than 10.”
But mashing together the different standards for place value and the number line is potentially confusing. “The number line is not an appropriate model for place value,” Zimba said.
The writing component is also problematic. “The standards don’t require essay writing in mathematics,” Zimba said.
The Common Core isn’t a curriculum, said Zimba. “The curriculum authors are going to interpret the standards in different ways.” Some of them will do it badly.
There’s going to be lots of bad implementation. It’s inevitable. Test scores will drop. That’s inevitable too, if only because the tests will be new and unfamiliar. Parents and teachers can share their frustrations on social media. Politicians are getting cold feet. Arne Duncan is out of bribe money. I think Common Core is in trouble.