Over the past year, since I took over the common-core math beat, I’ve been thinking a lot about fractions. As I wrote in November, the Common Core State Standards for mathematics emphasize fractions ...

Have you ever tried to add or subtract fractions that have different denominators? It’s tricky, right? Join Ms. Susanna Post in this lesson to learn how to solve these types of challenging problems!

We know there are individual differences in math ability, even at a young age, but what basic cognitive tools lay the foundation for whether we are good with numbers? And specifically, what basic ...