Math Mammoth Early Geometry (2026 edition)

Math Mammoth Early Geometry (2026 edition) is a worktext that covers geometry topics for grade 3. Being a worktext, it contains full instruction, written to the student, as well as a variety of problems and exercises. The book focuses on these three topics: classifying shapes, area, and perimeter. In the first three lessons of the book, students sort shapes into categories based on their attributes. They are learning, in particular, about quadrilaterals as a category. Next, we focus on the area of rectangles and shapes composed of rectangular areas. We start the topic with the lesson Getting Started with Area, where students tile shapes with unit squares cut out of paper, thus learning the foundation of how area is measured. From there, the lessons gradually lead to the thought that area of a rectangle can be found by multiplying its side lengths. Students learn about different units for area (both metric and customary) and get hands-on experience on finding the area of rectangles by measuring the sides in inches or centimeters. Then the lessons deal with the area of compound (rectilinear) shapes, whose area can be found by decomposing the shape into (non-overlapping) rectangles. The last major topic in the book is perimeter. Students learn perimeter as the “go-around measure”: the total distance when you go or travel around the shape. Then, several lessons focus on both area and perimeter, to make sure students learn to distinguish between these two concepts. We investigate rectangles that have the same area but different perimeters, and also rectangles that have the same perimeter but different areas. The answers are appended (at the end of the book).