Common Core’s Common Problem: When 5×3≠3×5

Common Core

Once again Common Core has hit the headlines, distressing us commoners and confusing us about everything we think we know with respect to math. What was the offending issue? 

Well it was simple: “Use the repeated addition strategy to solve : 5 x 3.”

Easy, right? Math that potentially I could do. Not so fast…

The child answered 15, with the repeated addition of “5 + 5 + 5” on the right-hand side. It looked fine to me, but the teacher deducted a point, writing that “3 + 3 + 3 + 3 + 3” was the right repeated addition. Then the Internet broke a little bit. The picture of the test was posted on imgur, viewed more than five million times and received comments like:

“There aren’t enough curse words in the English language for me to express how I feel about this.” 

and a simple 


While parents are still confused about whether this teacher deserves to keep her tertiary credentials, teachers who have been teaching Common Core have a more nuanced approach.

“I teach students that this number sentence says ‘5 groups of 3 is 15.’ Replace the times sign with the phrase “groups of” to help them differentiate between 5×3 and 3×5. Then they are able to demonstrate 3+3+3+3+3=15…,” One teacher wrote on our Facebook Page

The Business Insider website explained that this kind of question provides the building blocks for more complicated math, paving the way for a time when students learn matrices in multivariable calculus.  

Another teacher used our Facebook Page to elaborate on this: “The concept behind applying the same “rules” in third grade as those in higher math levels is to create a scope and sequence of learning. If students follow the rules from the beginning then as they start more complex math thinking they will make a smooth transition instead of having to forget elementary arithmetic rules and learn new, not meaningful rules.”

Others on our Page, remain unappeased. “Because CC is BS” wrote one user, while a separate user suggested that common core only makes sense in another dimension. 

Perhaps, Common Core has a bit of a PR problem. One user lamented over the fact that parents need to understand the reasoning behind Common Core as much as the students do.

Perhaps we have to be a bit more open to understanding math, our children’s way before we lose all of our points…and our marbles.

Marina Gomer is a journalist and mother of one.  She lives with her family in Sydney, Australia.