20. Divisibility 14
21. Solving Equations 32
22. Solving Inequalities 46
23. Venn diagrams 63
24. Combinatorics (Click here to see a sample) 83
25. Angles and triangles 104
26. Classification of triangles 115
27. Similar triangles 130
28. Pythagorean Theorem 147
29. Quadrilaterals 163
30. Trapezoids 177
31. Parallelograms 191
32. Angle bisectors and medians 205
33. Triangular inequality 218
34. Area Method 227
35. Polygons 241
36. Circles 262
Index 283