Number Power Series (Revised) The first choice for those who want to develop and improve their math skills. Every Number Power book targets a particular set of math skills with straightforward explanations, easy-to-follow, step-by-step instruction, real-life examples, and extensive reinforcement exercises. Use these texts across the full scope of the basic math curriculum, from whole numbers to pre-algebra and geometry. NUMBER 4: GEOMETRY Introduces lines, angles, triangles, and other plane figures, and solid figures.