This textbook includes the following contents: preparation, position, understanding and addition and subtraction of numbers within 10, understanding of graphics, understanding of numbers within1-20, understanding of clocks and watches, carrying addition within 20, and applying mathematics and mathematical practice.

The key teaching contents of this volume are addition and subtraction within 10 and carry addition within 20. These two parts and abdication subtraction within 20 (generally referring to one-digit addition and corresponding subtraction) are the beginning of students' learning to recognize numbers and calculate, and are widely used in daily life. At the same time, they are the basis of multi-digit calculation, the most basic content in primary school mathematics, the essential basic knowledge and skills for students' lifelong learning and development, and the ones that students must master.