Math Mammoth Geometry 1 covers all the typical geometry topics for grades 4-5: angles, triangles, quadrilaterals, other polygons, area, perimeter and volume. The book starts out by reviewing the third grade concepts of area and the perimeter of rectangles. Then, the book covers 4th grade topics, with a focus on angles. Students learn about lines, rays, and angles; and about acute, right, obtuse, and straight angles. They learn how to measure and draw angles with a protractor. We also study angle problems where students write simple equations. After that, students learn about parallelograms and other quadrilaterals in more detail, paying attention to their angles and lengths of sides. They also study triangles and classify them according to their angles. The latter half of the book covers 5th grade topics, focusing on two topics: classifying two-dimensional shapes, and volume. First, students classify figures into polygons and non-polygons, and also into regular polygons versus non-regular polygons. The next topic is classifying quadrilaterals. The focus is on understanding the classification, and understanding that attributes defining a certain quadrilateral also belong to all the “children” (subcategories) of that type of quadrilateral. Then we study the classification of triangles. Students are now able to classify triangles both in terms of their sides and also in terms of their angles. The second focus topic of this latter half is volume. Students learn that a cube with the side length of 1 unit, called a “unit cube,” is said to have “one cubic unit” of volume, and can be used to measure volume. They find the volume of right rectangular prisms by “packing” them with unit cubes and by using formulas. They recognize volume as additive and solve both geometric and real-word problems involving volume. The answer key is appended.