Ключевые слова: accuracy, background, centimeter, centimeters, chalk, chalkboard, college, color, copy, design, drafting, drawing, education, engineering, equipment, flat, geometry, green, instrument, knowledge, lay, learn, length, line, markings, math, mathematical, mathematics, measure, measurement, measuring, millimeter, nobody, number, object, precision, ruler, school, science, shape, space, stationery, supply, text, top, triangle, view, yellow,