Ключевые слова: addition, answer, black, blackboard, board, chalk, chalkboard, colorful, concept, conceptual, crumpled, drawing, educate, education, equal, equation, feeling, formula, friend, handwriting, heart, horizontal, icon, idea, interlaced, joined, learn, letter, love, math, mathematics, me, memo, nobody, note, notepaper, paper, plus, relationship, romance, sign, sticky, stickynotes, text, texture, together, valentine, white, word, you,