The revised edition of "The Math Book 3" consistently continues the path begun in the first two volumes into the third grade. The development of process-related competencies is furthered, as is the instruction in practical arithmetic. There is a targeted construction of the place value system within the number range up to 1000, complemented by numerous geometry pages and the development of size concepts. With a focus on the development of process-related competencies, the math book fully meets the requirements of the new curricula. This is particularly evident in the introductions to the central topics of "Addition and Subtraction in the Number Range up to 1000," "Written Addition," "Written Subtraction," and "Semi-written Multiplication and Division." Many tasks can be solved in partner or group work. The practice exercises are adapted to the new findings in learning psychology.