Standard Chinese is a set that is designed for Chinese heritage students aged 6-12 and could be commonly used in an elementary school in China. Here is a description from the publisher:
This textbook series，designed for Chinese heritage students aged 6-12, is divided into three levels with each level containing 3 textbooks. After finishing this series, students will have learned pinyin, and mastered 2000 characters, 5000 phrases and 300 basic sentences. The abilities of listening, speaking, reading and writing will be trained at the same time.