For five years, a San Francisco foundation funded, and a research organization closely monitored, a collaboration by 10 California districts to raise achievement under the Common Core math standards.

Compare and contrast these two assignments. Both target an 8th grade standard on seeing structure in an expression and being able to represent that expression in different ways. Which do you suppose ...

A correction to an earlier version of this article has been appended to the end of the article. When Veera Sinha was a little girl in India, her father asked his kids to solve math puzzles in their ...