Some people earn less than others. Once again, mathematical concepts will help you understand the world we live in, a world that is not always easy. What about you? Are you concerned about the well-being of others?
多媒體：
多媒體
互動練習
版面：
固定
插圖：
許多
關鍵字詞： Mathematics | operations | numbers | sequences | patterns | relationships | table of values