The third grade, the first volume of mathematics, look at the picture and write 24 squares. According to relevant data, the first volume of Grade Three Mathematics can draw 24 squares, mark numbers and cut heads. Time axis is an image representing age in history, and so is the number axis in mathematics. The biggest difference is that there is no number 0 on the historical time axis, and the mathematical number axis has 0 as the origin, which has the meaning of time, including the specific minutes, hours, days or years on the clock and calendar.