| Junior Puzzle #13 - One Possible Solution Approach… | |||||||||||
| NB: There is only one final solution to this Sudoku puzzle… | |||||||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | |||||||||||
| 2 | AA | BB | CC | Reference to 3x3 Blocks AA, BB & CC | |||||||
| 3 | |||||||||||
| 4 | |||||||||||
| 5 | DD | EE | FF | Reference to 3x3 Blocks DD, EE & FF | |||||||
| 6 | |||||||||||
| 7 | |||||||||||
| 8 | GG | HH | II | Reference to 3x3 Blocks GG, HH & II | |||||||
| 9 | |||||||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 7 | 1 | 4 | 8 | 5 | 9 | Junior Puzzle #13 - November 19, 2005 | |||
| 2 | 5 | 2 | 9 | 3 | 7 | 4 | 8 | Original puzzle as published © joe-ks.com | |||
| 3 | 4 | 8 | 5 | 2 | 1 | 7 | |||||
| 4 | 6 | 1 | 5 | 7 | 8 | ||||||
| 5 | 7 | 5 | 4 | 3 | 1 | 2 | 9 | 6 | |||
| 6 | 2 | 9 | 4 | 6 | 3 | 5 | |||||
| 7 | 8 | 2 | 7 | 1 | 4 | 5 | 3 | ||||
| 8 | 1 | 3 | 6 | 9 | 5 | 8 | 2 | ||||
| 9 | 9 | 4 | 5 | 2 | 6 | 7 | 1 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 7 | 1 | 4 | 8 | 5 | 9 | Step 1: Complete Block BB: #6 MUST go in Cell E3... | |||
| 2 | 5 | 2 | 9 | 3 | 7 | 4 | 8 | ||||
| 3 | 4 | 8 | 5 | 6 | 2 | 1 | 7 | Step 2: #7 is in Rows 4 & 5: #7 MUST go in Cell E6... | |||
| 4 | 6 | 1 | 5 | 7 | 8 | ||||||
| 5 | 7 | 5 | 4 | 3 | 1 | 2 | 9 | 6 | Step 3: #9 is in Rows 8 & 9: #9 MUST go in Cell G7… | ||
| 6 | 2 | 9 | 4 | 7 | 6 | 3 | 5 | ||||
| 7 | 8 | 2 | 7 | 1 | 4 | 9 | 5 | 3 | |||
| 8 | 1 | 3 | 6 | 9 | 5 | 8 | 2 | ||||
| 9 | 9 | 4 | 5 | 2 | 6 | 7 | 1 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 7 | 1 | 4 | 8 | 5 | 9 | Step 4: Complete Column C: #6 MUST go in Cell C7... | |||
| 2 | 5 | 2 | 9 | 3 | 7 | 4 | 8 | ||||
| 3 | 4 | 8 | 5 | 6 | 2 | 1 | 7 | Step 5: Complete Column E: #8 MUST go in Cell E5... | |||
| 4 | 6 | 1 | 5 | 7 | 8 | ||||||
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | Step 6: #8 is now in Columns E & F: #8 MUST go in Cell D9... | |
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 5 | |||
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | Step 7: #8 is now in Rows 4 & 5: #8 MUST go in Cell B6... | |
| 8 | 1 | 3 | 6 | 9 | 5 | 8 | 2 | ||||
| 9 | 9 | 4 | 5 | 8 | 2 | 6 | 7 | 1 | |||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 7 | 1 | 4 | 8 | 5 | 9 | Step 8: Complete Column A: #3 MUST go in Cell A4... | |||
| 2 | 5 | 2 | 9 | 3 | 7 | 4 | 8 | ||||
| 3 | 4 | 8 | 5 | 6 | 2 | 1 | 7 | Step 9: Complete Column D: #2 MUST go in Cell D4... | |||
| 4 | 3 | 6 | 1 | 2 | 5 | 7 | 8 | 4 | |||
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | Step 10: Complete Column I: #4 MUST go in Cell I4... | |
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 1 | 5 | ||
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | Step 11: Complete Row 6: #1 MUST go in Cell H6... | |
| 8 | 1 | 3 | 6 | 9 | 5 | 8 | 2 | ||||
| 9 | 9 | 4 | 5 | 8 | 2 | 6 | 7 | 1 | |||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 7 | 1 | 4 | 8 | 5 | 9 | Step 12: Complete Block EE: #9 MUST go in Cell F4... | |||
| 2 | 5 | 2 | 9 | 3 | 7 | 4 | 8 | ||||
| 3 | 4 | 8 | 5 | 6 | 2 | 1 | 7 | Step 13: Complete Block GG: #7 MUST go in Cell B8... | |||
| 4 | 3 | 6 | 1 | 2 | 5 | 9 | 7 | 8 | 4 | ||
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | Step 14: Complete Block HH: #3 MUST go in Cell F9... | |
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 1 | 5 | ||
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | Step 15: Complete Block II: #4 MUST go in Cell H8... | |
| 8 | 1 | 7 | 3 | 6 | 9 | 5 | 8 | 4 | 2 | ||
| 9 | 9 | 4 | 5 | 8 | 2 | 3 | 6 | 7 | 1 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 7 | 1 | 4 | 8 | 5 | 9 | Step 16: Complete Row 3: need #s 3 & 9… | |||
| 2 | 5 | 2 | 9 | 3 | 7 | 4 | 8 | #9 can't go in Cell H3 (cf #9 in Column H @ H5), so | |||
| 3 | 4 | 9 | 8 | 5 | 6 | 2 | 1 | 3 | 7 | #9 MUST go in Cell B3, & therefore #3 MUST go in Cell H3 | |
| 4 | 3 | 6 | 1 | 2 | 5 | 9 | 7 | 8 | 4 | ||
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | ||
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 1 | 5 | ||
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | ||
| 8 | 1 | 7 | 3 | 6 | 9 | 5 | 8 | 4 | 2 | ||
| 9 | 9 | 4 | 5 | 8 | 2 | 3 | 6 | 7 | 1 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 3 | 7 | 1 | 4 | 8 | 5 | 9 | Step 17: Complete Block AA: need #s 1 & 3… | ||
| 2 | 5 | 1 | 2 | 9 | 3 | 7 | 4 | 8 | #1 can't go in Cell B1 (cf #1 in Row 1 @ D1), so | ||
| 3 | 4 | 9 | 8 | 5 | 6 | 2 | 1 | 3 | 7 | #1 MUST go in Cell B2, & therefore #3 MUST go in Cell B1 | |
| 4 | 3 | 6 | 1 | 2 | 5 | 9 | 7 | 8 | 4 | ||
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | ||
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 1 | 5 | ||
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | ||
| 8 | 1 | 7 | 3 | 6 | 9 | 5 | 8 | 4 | 2 | ||
| 9 | 9 | 4 | 5 | 8 | 2 | 3 | 6 | 7 | 1 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 3 | 7 | 1 | 4 | 8 | 5 | 2 | 9 | Step 18: Complete Block CC (& Puzzle): need #s 2 & 6… | |
| 2 | 5 | 1 | 2 | 9 | 3 | 7 | 4 | 6 | 8 | #2 can't go in Cell H2 (cf #2 in Row 2 @ C2), so | |
| 3 | 4 | 9 | 8 | 5 | 6 | 2 | 1 | 3 | 7 | #2 MUST go in Cell H1, & therefore #6 MUST go in Cell H2 | |
| 4 | 3 | 6 | 1 | 2 | 5 | 9 | 7 | 8 | 4 | ||
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | ||
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 1 | 5 | ||
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | ||
| 8 | 1 | 7 | 3 | 6 | 9 | 5 | 8 | 4 | 2 | ||
| 9 | 9 | 4 | 5 | 8 | 2 | 3 | 6 | 7 | 1 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 6 | 3 | 7 | 1 | 4 | 8 | 5 | 2 | 9 | 45 | Final Proof: |
| 2 | 5 | 1 | 2 | 9 | 3 | 7 | 4 | 6 | 8 | 45 | - All Rows add up to 45; |
| 3 | 4 | 9 | 8 | 5 | 6 | 2 | 1 | 3 | 7 | 45 | |
| 4 | 3 | 6 | 1 | 2 | 5 | 9 | 7 | 8 | 4 | 45 | |
| 5 | 7 | 5 | 4 | 3 | 8 | 1 | 2 | 9 | 6 | 45 | |
| 6 | 2 | 8 | 9 | 4 | 7 | 6 | 3 | 1 | 5 | 45 | |
| 7 | 8 | 2 | 6 | 7 | 1 | 4 | 9 | 5 | 3 | 45 | |
| 8 | 1 | 7 | 3 | 6 | 9 | 5 | 8 | 4 | 2 | 45 | |
| 9 | 9 | 4 | 5 | 8 | 2 | 3 | 6 | 7 | 1 | 45 | |
| 45 | 45 | 45 | 45 | 45 | 45 | 45 | 45 | 45 | - All Columns add up to 45; | ||
| 45 | 45 | 45 | - All 3x3 Blocks add up to 45… | ||||||||
| 45 | 45 | 45 | |||||||||
| 45 | 45 | 45 | |||||||||
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