Students practice addition and subtraction problems without regrouping. In this lesson, students practice addition and subtraction problems without regrouping using base-10 block manipulatives and ...

A key part—though surely not the only part—of early-grades math is ensuring students get the basic arithmetic functions down and, beyond that, making sure they’re able to swiftly and automatically ...

The simplest ideas in mathematics can also be the most perplexing. Take addition. It’s a straightforward operation: One of the first mathematical truths we learn is that 1 plus 1 equals 2. But ...

A new proof illuminates the hidden patterns that emerge when addition becomes impossible. The simplest ideas in mathematics can also be the most perplexing. Take addition. It’s a straightforward ...