IM 6.2.6 Practice: Introducing Double Number Line Diagrams

① This example demonstrates how to use a double number line diagram to visually represent proportional relationships between two related quantities, such as unit price, speed, or recipe ratios. ② Core mathematical concepts include ratio, rate, unit conversion, and graphical representation of linear relationships, laying groundwork for later equations and functions. ③ Construction notes: Based on the summary, the example uses an image object (pic1), likely embedding a static diagram or background to show the structure of double number lines; in practice, teachers can use GeoGebra's segment, point, and text tools to draw two parallel number lines with corresponding tick marks. ④ Suitable for middle school (Grade 6) students learning ratio concepts, and useful for classroom demonstrations or independent practice, bridging concrete contexts to abstract proportional models.