Addition & subtraction strategies to solve two-digit equations using an open number line. In this lesson, students go over using different addition and subtraction strategies to solve two-digit ...

A number line can be useful when answering questions involving negative numbers. When adding a positive number, go up the number line (move to the right). When subtracting a positive number, go down ...

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 ...