The 20cm Math Addition and Subtraction Operations Ruler combines precisely measurement with built in addition / subtraction scales, offering multifunction measuring tool for accurate calculations and dometric drawing tasks Crafted from light weight yet sturdy, this addition and subtraction decomposition ruler features clearly numeric markings and rounded edges for in classrooms or Use during geometry classes, architectural drafting, or family homework hour to simplify measurements while developing numerical literacy through hands on learning Its fade resistant surfaces maintains visibility under varied lighting condition, ensuring durability whether sketching or teaching basic math mathematics concepts Ideal for students, engineering professional, and parent seeks educational tool, it bridges practical math applications with creative project, Manufacturer: Ywmsfl