The common-core math standards require that students learn the standard algorithm for multi-digit adding and subtracting—you know, the process in which you line the numbers up vertically to add or ...

Learn how to use first, then and now stories to understand addition. First, then, now (subtraction) Learn how to use first, then and now stories to understand subtraction problems. Subtraction within ...

Addition & subtraction with regrouping using different strategies to solve. In this lesson, students go over addition and subtraction with regrouping using different strategies to solve. Today we ...

Watch the video to learn about adding and subtracting with negative numbers on a number line and by using number discs. Adding and subtracting with negative numbers. Let's talk about two ways to help ...