Positive integer. The seventh grade is the first grade. In the course "Exponent of Power", the first volume of the seventh grade People's Education Edition, the range of exponent of power is a positive integer, which is set for the convenience of students' learning and understanding. People's Education Edition is the name of the textbook version compiled and published by the Institute of Curriculum Textbooks of People's Education Publishing House. The textbook of People's Education Edition covers the content from primary school to high school, and most schools are using it.