Ключевые слова: addition, background, banner, black, button, cancel, class, concept, correct, cross, data, delete, deny, error, exam, fail, failure, flat, gym, health, helicopter, hospital, icon, illustration, incorrect, isolated, learn, mark, maths, multiply, negative, net, no, not, objective, place, plus, prohibited, quiz, reject, remove, right, sign, spot, sum, symbol, warning, wrong, x,