| Junior Puzzle #7 - 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 | 4 | 7 | 9 | 3 | 5 | 2 | Junior Puzzle #7 - November 13, 2005 | ||||
| 2 | 9 | 2 | 3 | 6 | 4 | 7 | 1 | Original puzzle as published © joe-ks.com | |||
| 3 | 1 | 5 | 2 | 7 | 4 | 8 | 3 | ||||
| 4 | 5 | 4 | 1 | 2 | 6 | 3 | 8 | ||||
| 5 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | ||||
| 6 | 6 | 9 | 5 | 8 | 7 | 1 | 2 | ||||
| 7 | 4 | 8 | 6 | 5 | 1 | 3 | 9 | ||||
| 8 | 7 | 9 | 1 | 3 | 8 | 6 | 5 | ||||
| 9 | 6 | 5 | 7 | 8 | 2 | 1 | |||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 4 | 7 | 9 | 3 | 5 | 2 | Step 1: Complete Block AA: need #s 6 & 8… | |||
| 2 | 9 | 2 | 3 | 6 | 4 | 7 | 1 | #8 can't go in Cell C3 (see #8 in Row 3 @ H3), so | |||
| 3 | 1 | 5 | 6 | 2 | 7 | 4 | 8 | 3 | #8 MUST go in Cell A1, & therefore #6 MUST go in Cell C3 | ||
| 4 | 5 | 4 | 1 | 2 | 6 | 3 | 8 | ||||
| 5 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | Step 2: Complete Block GG: need #s 2 & 3… | |||
| 6 | 6 | 9 | 5 | 8 | 7 | 1 | 2 | #3 can't go in Cell C7 (cf #3 in Row 7 @ H7), so | |||
| 7 | 4 | 8 | 2 | 6 | 5 | 1 | 3 | 9 | #3 MUST go in Cell A9, & therefore #2 MUST go in Cell C7 | ||
| 8 | 7 | 9 | 1 | 3 | 8 | 6 | 5 | ||||
| 9 | 3 | 6 | 5 | 7 | 8 | 2 | 1 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 4 | 7 | 9 | 3 | 5 | 2 | 6 | Step 3: Complete Block CC: need #s 6 & 9… | ||
| 2 | 9 | 2 | 3 | 6 | 4 | 7 | 1 | #9 can't go in Cell I1 (cf #9 in Row 1 @ D1), so | |||
| 3 | 1 | 5 | 6 | 2 | 7 | 4 | 9 | 8 | 3 | #9 MUST go in Cell G3, & therefore #6 MUST go in Cell I1 | |
| 4 | 5 | 4 | 1 | 2 | 6 | 3 | 8 | ||||
| 5 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | Step 4: Complete Block II: need #s 4 & 7… | |||
| 6 | 6 | 9 | 5 | 8 | 7 | 1 | 2 | #7 can't go in Cell I9 (cf #7 in Row 9 @ D9), so | |||
| 7 | 4 | 8 | 2 | 6 | 5 | 1 | 7 | 3 | 9 | #7 MUST go in Cell G7, & therefore #4 MUST go in Cell I9 | |
| 8 | 7 | 9 | 1 | 3 | 8 | 6 | 5 | ||||
| 9 | 3 | 6 | 5 | 7 | 8 | 2 | 1 | 4 | |||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 4 | 7 | 9 | 1 | 3 | 5 | 2 | 6 | Step 5: Complete Row 1: #1 MUST go in Cell E1... | |
| 2 | 9 | 2 | 3 | 6 | 4 | 7 | 1 | ||||
| 3 | 1 | 5 | 6 | 2 | 7 | 4 | 9 | 8 | 3 | Step 6: Now complete Column E: #9 MUST go in Cell E9… | |
| 4 | 5 | 4 | 1 | 2 | 6 | 3 | 8 | ||||
| 5 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | 7 | Step 7: Complete Column I: #7 MUST go in Cell I5… | ||
| 6 | 6 | 9 | 5 | 8 | 7 | 1 | 2 | ||||
| 7 | 4 | 8 | 2 | 6 | 5 | 1 | 7 | 3 | 9 | ||
| 8 | 7 | 9 | 1 | 3 | 8 | 6 | 5 | ||||
| 9 | 3 | 6 | 5 | 7 | 9 | 8 | 2 | 1 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 4 | 7 | 9 | 1 | 3 | 5 | 2 | 6 | Step 8: Complete Column A: #2 MUST go in Cell A5… | |
| 2 | 9 | 2 | 3 | 8 | 6 | 5 | 4 | 7 | 1 | ||
| 3 | 1 | 5 | 6 | 2 | 7 | 4 | 9 | 8 | 3 | Step 9: Complete Block BB: need #s 5 & 8… | |
| 4 | 5 | 4 | 1 | 2 | 6 | 3 | 9 | 8 | #5 can't go in Cell D2 (cf #5 in Column D @ D6), so | ||
| 5 | 2 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | 7 | #5 MUST go in Cell F2, & therefore #8 MUST go in Cell D2 | |
| 6 | 6 | 9 | 5 | 8 | 7 | 1 | 4 | 2 | |||
| 7 | 4 | 8 | 2 | 6 | 5 | 1 | 7 | 3 | 9 | Step 10: Complete Block FF: need #s 4 & 9… | |
| 8 | 7 | 9 | 1 | 3 | 8 | 6 | 5 | #4 can't go in Cell H4 (cf #4 in Row 4 @ C4), so | |||
| 9 | 3 | 6 | 5 | 7 | 9 | 8 | 2 | 1 | 4 | #4 MUST go in Cell H6, & therefore #9 MUST go in Cell H4 | |
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 4 | 7 | 9 | 1 | 3 | 5 | 2 | 6 | Step 11: Complete Row 4: #7 MUST go in Cell B4... | |
| 2 | 9 | 2 | 3 | 8 | 6 | 5 | 4 | 7 | 1 | ||
| 3 | 1 | 5 | 6 | 2 | 7 | 4 | 9 | 8 | 3 | Step 12: Complete Row 6: #3 MUST go in Cell B6... | |
| 4 | 5 | 7 | 4 | 1 | 2 | 6 | 3 | 9 | 8 | ||
| 5 | 2 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | 7 | Step 13: Complete Column D: #4 MUST go in Cell D8... | |
| 6 | 6 | 3 | 9 | 5 | 8 | 7 | 1 | 4 | 2 | ||
| 7 | 4 | 8 | 2 | 6 | 5 | 1 | 7 | 3 | 9 | Step 14: Complete Column F (& Puzzle): | |
| 8 | 7 | 9 | 1 | 4 | 3 | 2 | 8 | 6 | 5 | #2 MUST go in Cell F8. | |
| 9 | 3 | 6 | 5 | 7 | 9 | 8 | 2 | 1 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 4 | 7 | 9 | 1 | 3 | 5 | 2 | 6 | 45 | Final Proof: |
| 2 | 9 | 2 | 3 | 8 | 6 | 5 | 4 | 7 | 1 | 45 | - All Rows add up to 45; |
| 3 | 1 | 5 | 6 | 2 | 7 | 4 | 9 | 8 | 3 | 45 | |
| 4 | 5 | 7 | 4 | 1 | 2 | 6 | 3 | 9 | 8 | 45 | |
| 5 | 2 | 1 | 8 | 3 | 4 | 9 | 6 | 5 | 7 | 45 | |
| 6 | 6 | 3 | 9 | 5 | 8 | 7 | 1 | 4 | 2 | 45 | |
| 7 | 4 | 8 | 2 | 6 | 5 | 1 | 7 | 3 | 9 | 45 | |
| 8 | 7 | 9 | 1 | 4 | 3 | 2 | 8 | 6 | 5 | 45 | |
| 9 | 3 | 6 | 5 | 7 | 9 | 8 | 2 | 1 | 4 | 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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