My children use Tianxing's "primary school once". At that time, when I chose the supplementary books, I was attracted by the exquisite design of this set of books, and the children also liked the pictures in the books, which was very interesting. The setting of test questions in this set of books feels quite scientific. Class hours are closely related to the content learned, and the test questions are easy, but the synthesis of unit test questions is difficult. In addition, there is a set of assessment papers, which can help children check for missing items. The quality of the test questions is also very high. I attach great importance to the examination of mathematical thinking, and the answers are also analyzed in detail. In short, it's good, and my children like it very much.