Students go over addition and subtraction with regrouping using different strategies. In this lesson, students go over addition and subtraction with regrouping using different strategies to solve.

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 ...

Take this quiz to see how much you know about this topic already, then work through the guide and see if you can beat your score. Take a look at this number line. It shows 14 - 5 = 9. You can count ...

Here is a part-whole model. Sometimes the model is rotated. It looks different, but it still has two parts and a whole. We can use this model to help us solve problems. We can put 4 things in one of ...