Features: 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 plastic, this addition and subtraction decomposition ruler features clearly numeric markings and rounded edges for scratch resistant safety in classrooms or office. Ideal for STEM students, engineering professional, and parent seeks educational tool, it bridges practical math applications with creative project. 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. Specifications: Component: Plastic Color: Blue, Pink, Purpler, Green Size: Approx. 27cm/10.62in Measuring Length: 0-20cm Weight: Approx. 20g Package Includes: 1Piece Math Calculation Ruler note: 1.Please allow 0-1cm error due to manual measurement. Be sure you donot mind before bid. 2.Due to difference between different monitors, the picture may not reflect the actual color