Math Mammoth Early Geometry is a worktext that covers geometry topics for grades 1-3.
The first lessons in the book have to do with shapes. Children learn to identify and draw basic shapes. Using cut-out shapes, they put several shapes together to form new ones. They also divide existing shapes into new ones by drawing a line in shapes. Students also explore some geometric patterns and make shapes in a tangram-like game.
Starting from the lesson Polygons, the lessons are for third grade level. In the first three lessons of this section, students sort shapes into categories based on their attributes, and learning, in particular, about quadrilaterals as a category.
Next, we focus on the area of rectangles and shapes composed of rectangular areas. In the lesson Getting Started with Area, 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.
In this context, we also study the distributive property in disguise. A rectangle is divided into two parts, and its area is found in two different ways: either as the area of the entire rectangle, or by adding the areas of the two parts.
The last major topic in the book is perimeter. Students learn perimeter as the Ògo-around measureÓ: 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.