This page is devoted to outlining corrections to the first print of “Puzzle Based Learning”.

1. Page 22, 2^nd line after the figure with 12 matches.  Modify the sentence “For further discussion on this problem, see…”  by adding a few words:  “For further discussion on this problem and more logical approaches to solving this puzzle, see…”
2. Page 45, 16^th line from the bottom.  Replace “B” by “C”, so the end of the sentence would be:  “…and the switchC controls bulb z.”
3. Page 50. Replace the first paragraph by the following:  “The problem description does not make it clear that the particular arrival time x of the bus in the period 7:58 ≤ x ≤ 8:02 is equally likely, nor that the particular arrival time yof the boy in the period 7:55 ≤ y ≤ 8:01 is equally likely. In cases like that it is reasonable to invoke the principle of indifference which says that unless there is a reason for believing otherwise, each possible event should be regarded as equally likely. In other words, it is reasonable to assume a uniform distribution of arrival times in intervals (7:58, 8:02) and (7:55, 8:01), for the bus and the boy, respectively.”
4. Page 61. 4^th line above the Puzzle 4.2. Replace “(50, 51)” by “(50 and 51)”.
5. Page 63, 6^th line from the top. Remove “)” after the word “respectively”.
6. Page 64, 7^th line from the top. Remove the remaining part of the whole paragraph after the sentence: “This is the invariant we are searching for!” After this sentence (which stays in the text) we continue with: “Now, note that the dragon can be killed by reaching any of termination points: 15, 17, 20, or 5 with the given rules. We call them termination points because one application of the appropriate cut kills the dragon. But getting to those termination points requires reducing the original number of dragon’s heads by 85, 83, 80, or 95, respectively. And those reductions are all impossible, because none of those reductions is by a factor of 3… So it is not possible to kill the dragon!”
7. Page 68. Last line of the first paragraph. Replace “…in the case of k cars.” by “…in the case of k stations.”
8. Page 73. Second to last paragraph. Replace the sentence: “Let us conclude this chapter with two puzzles, which might illustrate the difference between vertical and lateral thinking.” by “Let us conclude this chapter with a puzzle and a joke, which might illustrate the difference between vertical and lateral thinking.”
9. Page 74. Beginning of the 3^rd paragraph. Replace “The second puzzle” by “The second “puzzle”” (i.e. include the world “puzzle” in quotation signs).
10. Page 80, 13^th line from the top.  Replace the sentence: “Indeed, there is only one case (the product of 120) that has three different sequences:”  by “Of these cases (six with 2 different sequences and two with 3 different sequences), only one (the product of 120) involves differing number of children in the Black family:”
11. Page 80, few lines later. Replace: “Clearly, Mr. Blue’s apartment number must have been 120; otherwise Mr. White would not have asked for any additional information. Remember that he asked: “Is there more than one child in the Black family?”” by “Clearly, Mr. Blue’s apartment number must have been 120; otherwise Mr. White would not have asked: “Is there more than one child in the Black family?””.
12. Page 97, 6^th line from the top. Replace:  “Say we now selected the first column and the second row; the value of this cell is represented by the variable y. Since the numbers 1, 2, 4, 5, 7, 8, and 9 are already present in either in the first column or in the second row, we can conclude that y can only take one of the two remaining values: 3 or 6. Again, we can assign y = 3 and move forward.” by “Say we now selected the second column and the fifth row; the value of this cell is represented by the variable y. Since the numbers 1, 2, 3, 5, 6, and 8 are already present in the first column or in the second row or in the 3 × 3 box, we can conclude that y can only take one of the three remaining values: 4, 7 or 9. Again, we can assign y = 4 and move forward.”
13. Page 105, 2^nd paragraph from the bottom. In this paragraph, there are occurrences of the word blue (in italic) – in lines 4 and 5 of this paragraph.  Replace both occurrences of blue by black.
14. Page 116, 4^th line from the bottom. Replace “through to famous” by “through the famous”.
15. Page 125. The picture of the box – one edge is missing.
16. Page 134, 19^th line from the top. After the word ‘assume’ add “(again, the principle of indifference)”.
17. Page 135. 6^th line from the top. Replace 1/3 by 1/2.
18. Page 164. In the table, row number 9, the last two columns. Replace single S by SSSS and double NN by N.
19. Page 178. Remove the footnote.
20. Page 181, 6^th line from the bottom. Replace 10 by 11.
21. Page 194, 15^th line from the bottom. Replace the sentence “The last two puzzles illustrate the fact that many pattern recognition activities are based on a priori knowledge.” by  a few sentences: “Of course, there are other possible solutions one can justify – for example, a ‘valid’ pattern is obtained by replacing ? with C. Note then that we have A_CD_FGH_JKL, where the underscores indicate a missing letter after 1, then 2, then 3 (and then presumably so on) spaces. Other possible solutions may require justification of more complex patterns… However, the purpose of this (and the previous) puzzle was just to illustrate the fact that many pattern recognition activities are based on a priori knowledge.”
22. Page 205. First line of puzzle 10.12. Replace two occurrences of “three” by “four”.
23. Page 209. First line of puzzle 10.14. Replace two occurrences of “three” by “n”.
24. Page 213, at the top, after the quote. Replace “The Man with Twisted Lip” by “The Man with the Twisted Lip”.
25. Page 215, 5^th line after the first picture – text of puzzle 11.1. Replace “can remove one or two…” by “can remove one or more…”.
26. Page 216, 8^th line from the bottom. Replace the first occurrence of “player A” by “player B”.
27. Page 220, 4^th line of the text of puzzle 11.4. Replace “take” by “takes”.
28. Page 222, 9^th line from the bottom. Replace “Position (3,2,1):    2 = (11)₂” by  “Position (3,2,1):    3 = (11)₂”.
29. Page 222, 7^th line from the bottom. Replace “0 = (01)₂” by  “1 = (01)₂”.
30. Page 223, lines 7^th, 8^th, and 9^th from the bottom. These lines are arranged as a table with 3 rows and 4 columns, each entry is a binary sequence like (1001100). Remove 2^nd, 3^rd, and 4^th column – just leave only the first column.
31. Page 228, last sentence of the first paragraph of the description of Puzzle 11.7. Replace “At each turn, the participant who is firing may aim at any of the other two participants.” by “At each turn, the participant who is firing may fire only one shot in the direction of his choosing.”
32. Page 253, 4^th line of the text of Puzzle 12.5. Replace “If the number appears once, you recover your bet.” by “If the number appears once, you win $1.”
33. Page 253, 14^th line from the bottom (formula). Replace two occurrences of 126 by 216.
34. Page 262, 17^th line from the top. Replace “However, none of these three possibilities would result in three liars, so C cannot be a liar…” by “However, none of these three possibilities would result in three truth-tellers, so Ccannot be a liar…” (e.g. replace ‘liars’ by ‘truth-tellers’).
35. Page 272, 12^th line from the bottom.  Replace part of the sentence “This is a time- exercise that when complete, …” by “This is a time-consuming exercise which on completion …” (remember to remove comma).
36. Page 291, 2^nd line after the first figure. Change ≥ to >.
37. Page 291, 3^rd line after the first figure. Change < to ≤.
38. Page 291, 2^nd line after the second figure. Change ≥ to >.
39. Page 291, 3^rd line after the third figure. Replace “If so is,” by “If it is,”
40. Page 291, 3^rd line after the third figure.  Remove the phrase “or equal” from the sentence.
41. Page 291, beginning of the 4^th line after the third figure.  After ‘then’ add “or equal to”.
42. Page 293, 13^th line from the top. Replace “Mr. Purple” by “Mr. Brown”.
43. Page 295, the footnote is not complete. The end of this sentence should be “…so the age of the monkey (for example) might be 1 ¾.”
44. Page 298, just before the text of Puzzle 12.29. Replace the sentence “Let us return to fascinating topic of counting children; this time we are after the number of children of Mr. Green” by “Let us return to fascinating topic of counting children; this time we are after the ages of Mr. Green’s children.”.
45. Page 299, 13^th line from the top. Replace 10 by 9.
46. Page 299, 14^th line from the bottom. Replace “There are only four” by “There are only five”.
47. Page 299, 8^th line from the bottom. Add additional (5^th) line in the ‘table’  of Product and Possibilities, which is:  36    (6,6) or (4,9)
48. Page 299, 6^th line from the bottom. Replace ‘8 cases’ by ’10 cases”.
49. Page 299, last line, last character. Replace 8 by 10.
50. Page 300, 3^rd line. Replace ‘8 cases’ by ’10 cases”.
51. Page 300, the first table of ‘Possibility’ and ‘Total’. Extend this table by two additional lines, which are:  (6,6) 12  and (4,9)  13
52. Page 300, first line after the above table. Replace “Now, if Mr. White’s son was 7 or 9,” by “Now, if Mr. White’s son was 7, 9, 12, or 13,”
53. Page 300, the sentence between the second and third tables. Replace “This was an important hint for Mr. Black: now he knows that he can eliminate three cases (3, 4) and (3, 6).” by “This was an important hint for Mr. Black: now he knows that he can eliminate four cases (3, 4), (3, 6), (4, 9), and (6, 6).”
54. Page 302, 3^rd line from the top. Replace 4¹³⁸ by 4¹³⁶.
55. Page 305, text of Puzzle 13.1. Replace three occurrences of ‘sliding’ by ‘siding’.
56. Page 310, 4^th line from the top.  Replace ‘sliding’ by ‘siding’.
57. Page 312, the sentence just before Puzzle 13.23. Add ‘the’ before word ‘zebra’.
58. Page 312, the text of Puzzle 13.23. In sentence # 4 replace “Mr. Orange” by “the man who ordered beer”.
59. Page 312, the text of Puzzle 13.23. In sentence # 7 replace ‘red wine’ by ‘coca cola’.
60. Page 316, text of Puzzle 13.35. In the dialog, change the last two sentences; the dialog should be:

– There is a fire in one of the villages!

– Which village is on fire?

– Our village is!

– Which is?

– Village C…

61. Page 325. Remove reference of the author P.L. Chessin.
62. Page 327. Add index entry “Indifference principle” with pages 50, 134.