Introduction; 1. Matchstick triangles; 2. A tricky river crossing; 3. The baffled engine driver; 4. Make your own dice; 5. Map folding; 6. The ingenious milkman; 7. Pawns on a chessboard; 8. Avoid three (a game for two players); 9. Two halves make a whole; 10. Cubism; 11. Matchstick squares; 12. Curves of pursuit (a geometric construction); 13. The misguided missiles (an extension of 12); 14. Pattern; 15. The army's predicament; 16. The farmer's sheep-pens; 17. The knight's dance; 18. The railway sidings; 19. The multi-coloured cube; 20. The jealous husbands; 21. The extension lead; 22. Hex (a game for two players); 23. The square, cross and circle; 24. The Möbius band (a practical activity); 25. The economical gardener; 26. How many triangles can you see?; 27. The unfriendly power-boats; 28. The knight-guards; 29. Reserving the trains; 30. Quadruplets; 31. Complete the square; 32. Roll a penny; 33. The growing network (a game for two players); 34. Traversibility; 35. Impossible rotations!; 36. The hunter; 37. Four points in a plane; 38. The letter dice; 39. The queen's defence; 40. Seeing is believing; 41. Inspecting the roads; 42. Dominoes on a chessboard; 43. Zigzag (a game for two players); 44. Knight's tours; 45. Sawing up a cube; 46. The improbable hole; 47. Identical twins; 48. The four-colour theorem; 49. Mystifying matchsticks; 50. Equilateral triangle to square; 51. Squaring the urn; 52. The baffled housewife; 53. Invert the triangle; 54. Avoid that snooker; 55. Squares (a game for two players); 56. The hungry bookworm; 57. Place the motorway junction; 58. Space filling; 59. Curves from intersecting circles (attractive geometrical constructions); 60. A lover's ultimatum!; 61. Only four lines; 62. How fast can you cycle?; 63. The bob-sleigh run; 64. Know your vowels; 65. Games on a pegboard for one to play; 66. Two of a kind; 67. Colouring a cube; 68. Problems of single line working; 69. Two at a time; 70. Heads and tails; 71. Square a Greek cross; 72. The fuel delivery; 73. Fair shares; 74. Coin magic; 75. The persistent frog; 76. Tidy that bookshelf!; 77. Cutting up a circle; 78. Square relations; 79. The numerate gardener; 80. Magic triangles; 81. Number patterns; 82. Surprising subtractions; 83. How large a number can you get?; 84. Four 4s; 85. What was the sum?; 86. Calculator words; 87. A calculator crossword; 88. A mining bonanza; 89. Hundreds, tens and units; 90. Magic circles; 91. Prelude to a marathon; 92. Find the digits; 93. Dr Numerati's telephone number; 94. Make a century; 95. Number wheels; 96. Some calculator challenges; 97. Division patterns; 98. Some named numbers; 99. Magic stars; 100. Safety first; 101. The gambler's secret strategy; 102. The transportation problem; 103. Further number patterns; 104. Pythagorean triads; 105. Intriguing multiplications; 106. A magic diamond; 107. Palindromic dates; 108. 'Mind reading' number cards (a number trick to make and use); 109. 3 x 3 magic squares; 110. 4 x 4 and higher order magic squares; 111. A magic cube; 112. A question of balance; 113. Further calculator challenges; 114. A weighing problem; 115. Similar rectangles; 116. Designing a new dartboard; 117. The only magic hexagon; 118. Nim (a game for two players); 119. Triangulating a square; 120. Who is 'it'?; 121. Find the cards on the table; 122. Dividing the inheritance; 123. The end of the world!; 124. The sponsored marathon; 125. The effect of inflation; 126. Octogenarian occupations; 127. Tails up!; 128. Dovetailed; 129. More matchstick mindbenders; 130. Bridging the river.