Ключевые слова: 3, arithmetic, background, bold, bright, clarity, clean, clear, contrast, copy space, counting, design, digit, display, distinct, easy, education, figure, icon, isolated, learning, math, minimalism, noticeable, number, numeral, numeric, object, plastic, prominence, readability, red, school, shadow, shape, simple, standout, stark, striking, strong, symbol, three, tool, typography, vibrant, visibility, visual, white,