Jointly developed with the teacher, the "Teacher Recommended Ruler" series [Triangular rulers only] The right-angle corner of the triangular ruler has a 0 (zero) marking, making it easy to use. This item was used by a child. [Set Contents] • Right isosceles triangular ruler • Right-angled triangular ruler To prevent bending, we will add cardboard or corrugated cardboard for shipping. #ruler #triangular ruler #isosceles triangle #Reimei #Raymay #Raymay #zeromarking #zeroscale #school lesson #arithmetic #mathematics