"Easy Learning Olympic Mathematics" has a strong level and is easy for children to accept. "Draw inferences from others" A pays too much attention to imitation, which is not conducive to the cultivation of children's innovative thinking. If it is not suitable for math major, you can use B. The "step expansion" of 60 points is too jumping and must be paved, so it is suggested that mathematics majors can use "easy to learn Olympic mathematics", and if not, they can use "draw inferences from others".