Adding Signed Numbers: Vector Demonstration on the Number Line

This GeoGebra example visually demonstrates the addition of signed numbers (positive and negative integers) using vectors on a number line. The core mathematical concept is the arithmetic of rational numbers, focusing on how signs and absolute values combine during addition. Construction details: Points A, B, C, D are created on the number line using the Point command, and vectors u, w, v are constructed with the Vector command. Vectors u and w represent the two addends as directed displacements (signed numbers), while vector v represents their sum. By dragging points or sliders to change the signs and magnitudes of the addends, learners observe the tip-to-tail vector addition and see how the final position reflects the rules: same signs add and keep the sign, opposite signs subtract and take the sign of the larger absolute value. This resource is ideal for middle school (Grade 7) students learning rational number operations, and serves as an interactive tool for teachers to bridge geometric intuition and algebraic rules.