| Easy Puzzle #10 - One Possible Solution Approach… | |||||||||||
| NB: There is only one final solution to this Sudoku puzzle… | |||||||||||
| Rules: Place a number from 1-9 in each empty cell so that each row, each column AND each 3x3 block contains all the numbers from 1-9. | |||||||||||
| 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 | 8 | 1 | 3 | Easy Puzzle #10 - October 10, 2005 | |||||||
| 2 | 9 | 4 | 3 | 2 | 7 | Original puzzle as published on joe-ks.com… | |||||
| 3 | 2 | 5 | 4 | 9 | |||||||
| 4 | 6 | 8 | 3 | 5 | |||||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | |||||
| 6 | 7 | 8 | 1 | 6 | |||||||
| 7 | 7 | 2 | 8 | 3 | 9 | 1 | |||||
| 8 | 5 | 1 | 3 | ||||||||
| 9 | 6 | 5 | 2 | 8 | 7 | ||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 3 | Step 1: #2 is in Columns A & C: #2 MUST go in Cell B6… | |||||||
| 2 | 9 | 4 | 3 | 2 | 7 | ||||||
| 3 | 2 | 8 | 5 | 4 | 9 | Step 2: #8 is in Columns D & F: #8 MUST go in Cell E3 | |||||
| 4 | 6 | 8 | 3 | 9 | 5 | (cf #8 in Row 1 @ C1 excludes use of Cell E1) | |||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | |||||
| 6 | 2 | 7 | 8 | 1 | 6 | Step 3: #9 is in Columns G & I: #9 MUST go in Cell H4… | |||||
| 7 | 7 | 2 | 8 | 3 | 9 | 1 | |||||
| 8 | 5 | 1 | 3 | ||||||||
| 9 | 6 | 5 | 2 | 8 | 7 | ||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 3 | Step 4: #8 is in Rows 1 & 3: #8 MUST go in Cell H2… | |||||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | |||||
| 3 | 2 | 8 | 5 | 4 | 9 | Step #5: #5 is in Rows 8 & 9: #5 MUST go in Cell H7… | |||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | Step #6: Complete Block DD: need #s 3 & 4… | ||||
| 6 | 3 | 2 | 7 | 8 | 1 | 6 | #3 can't go in Cell C4 (cf #3 in Row 4 @ G4), so | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | #3 MUST go in Cell A6, & therefore #4 MUST go in Cell C4 | |||
| 8 | 5 | 1 | 3 | ||||||||
| 9 | 6 | 5 | 2 | 8 | 7 | ||||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 6 | 3 | Step 7: Complete Column H: #6 MUST go in Cell H1… | ||||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | |||||
| 3 | 2 | 8 | 5 | 4 | 9 | Step 8: Now #6 is in Columns H & I: #6 MUST go in Cell G8… | |||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 2 | 8 | Step 9: Block GG needs #1: #1 can't go in Cells B7 or B9 | ||||
| 6 | 3 | 2 | 7 | 8 | 1 | 6 | (cf #1 in Column B @ B5) nor in Cells A8 or C8 | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | (cf #1 1 in Row 8 @ F8): only cell left for #1 is @ A9… | |||
| 8 | 5 | 1 | 6 | 3 | |||||||
| 9 | 1 | 6 | 5 | 2 | 8 | 7 | |||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 6 | 3 | Step 10: Complete Block FF: need #s 4 & 7… | ||||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | #7 can't go in Cell G6 (cf #7 in Row 6 @ C6), so | ||||
| 3 | 2 | 8 | 5 | 4 | 9 | #7 MUST go in Cell G5, & therefore #4 MUST go in Cell G6 | |||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 11: Complete Block II: need #s 2 & 4… | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | #2 can't go in Cell I9 (cf #2 in Row 9 @ F9), so | |||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | #2 MUST go in Cell I8, & therefore #4 MUST go in Cell I9 | |||
| 8 | 5 | 1 | 6 | 3 | 2 | ||||||
| 9 | 1 | 6 | 5 | 2 | 8 | 7 | 4 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 12: Complete Block CC: need #s 1 & 5… | |||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | #1 can't go in Cell G1 (cf #1 in Row 1 @ D1), so | ||||
| 3 | 2 | 8 | 5 | 1 | 4 | 9 | #1 MUST go in Cell G3, & therefore #5 MUST go in Cell G1 | ||||
| 4 | 6 | 8 | 4 | 3 | 9 | 5 | |||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 13: #9 is in Columns A & B: #9 MUST go in Cell C8… | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | ||||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 6 | 5 | 2 | 8 | 7 | 4 | ||||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 14: Row #4 needs #1: #1 MUST go in Cell E4 | |||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | (#1 in Column D @ D1 excludes use of Cell D4, and | ||||
| 3 | 2 | 8 | 5 | 1 | 4 | 9 | #1 in Column F @ F8 excludes use of Cell F4) | ||||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | ||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 15: Row #9 needs #9: #9 MUST go in Cell D9 | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | (cf #9 in Column B @ B2 excludes use of Cell B9) | |||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | ||||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | |||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 16: Complete Row 9: #3 MUST go in Cell B9… | |||||
| 2 | 9 | 4 | 3 | 2 | 8 | 7 | |||||
| 3 | 2 | 3 | 8 | 5 | 1 | 4 | 9 | Step 17: #3 is in Rows 1 & 2: #3 MUST go in Cell C3… | |||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | (cf Step 16's #3 excludes use of Cell B3) | |||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | ||||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 2 | 8 | 3 | 9 | 5 | 1 | ||||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 18: Complete Column C: #1 MUST go in Cell C2… | |||||
| 2 | 9 | 1 | 4 | 3 | 2 | 8 | 7 | ||||
| 3 | 2 | 3 | 8 | 5 | 1 | 4 | 9 | Step 19: #6 is in Rows 8 & 9: #6 MUST go in Cell F7… | |||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | ||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | ||||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | |||
| 8 | 5 | 9 | 1 | 6 | 3 | 2 | |||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 8 | 1 | 5 | 6 | 3 | Step 20: Complete Row 7: #4 MUST go in Cell B7… | |||||
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | ||
| 3 | 2 | 3 | 8 | 5 | 1 | 4 | 9 | Step 21: 1 cell left in Block GG: #8 MUST go in Cell A8… | |||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | ||||
| 5 | 9 | 1 | 5 | 6 | 7 | 2 | 8 | Step 22: Complete Row 2: need #s 5 & 6 | |||
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | #6 can't go in Cell A2 (cf #6 in Column A @ A4), so | |||
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | #6 MUST go in Cell D2, & therefore #5 MUST go in Cell A2 | |
| 8 | 8 | 5 | 9 | 1 | 6 | 3 | 2 | ||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 4 | 8 | 1 | 5 | 6 | 3 | Step 23: Complete Column A: #4 MUST go in Cell A1… | ||||
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | ||
| 3 | 2 | 3 | 8 | 5 | 1 | 4 | 9 | Step 24: Complete Row 5: need #s 3 & 4… | |||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | #3 can't go in Cell F5 (cf #3 in Column F @ F2), so | |||
| 5 | 9 | 1 | 5 | 3 | 6 | 4 | 7 | 2 | 8 | #3 MUST go in Cell D5, & therefore #4 MUST go in Cell F5 | |
| 6 | 3 | 2 | 7 | 8 | 4 | 1 | 6 | ||||
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | ||
| 8 | 8 | 5 | 9 | 1 | 6 | 3 | 2 | ||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 4 | 8 | 1 | 5 | 6 | 3 | Step 25: #6 is in Rows 1 & 2: #6 MUST go in Cell B3… | ||||
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | ||
| 3 | 2 | 6 | 3 | 8 | 5 | 1 | 4 | 9 | Step 26: Complete Row 6: need #s 5 & 9… | ||
| 4 | 6 | 8 | 4 | 1 | 3 | 9 | 5 | #5 can't go in Cell E6 (cf #5 in Column # @ E9), so | |||
| 5 | 9 | 1 | 5 | 3 | 6 | 4 | 7 | 2 | 8 | #5 MUST go in Cell D6, & therefore #9 MUST go in Cell E6 | |
| 6 | 3 | 2 | 7 | 5 | 9 | 8 | 4 | 1 | 6 | ||
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | ||
| 8 | 8 | 5 | 9 | 1 | 6 | 3 | 2 | ||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 4 | 7 | 8 | 1 | 5 | 6 | 3 | Step 27: Complete Block AA: #7 MUST go in Cell B1… | |||
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | ||
| 3 | 2 | 6 | 3 | 8 | 5 | 1 | 4 | 9 | Step 28: Complete Block EE: need #s 2 & 7 | ||
| 4 | 6 | 8 | 4 | 2 | 1 | 7 | 3 | 9 | 5 | #2 can't go in Cell F4 (cf #2 in Column F @ F9), so | |
| 5 | 9 | 1 | 5 | 3 | 6 | 4 | 7 | 2 | 8 | #2 MUST go in Cell D4, & therefore #7 MUST go in Cell F4 | |
| 6 | 3 | 2 | 7 | 5 | 9 | 8 | 4 | 1 | 6 | ||
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | ||
| 8 | 8 | 5 | 9 | 1 | 6 | 3 | 2 | ||||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 4 | 7 | 8 | 1 | 5 | 6 | 3 | Step 29: Complete Block HH: need #s 4 & 7… | |||
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | #4 can't go in Cell E8 (cf #4 in Column E @ E2), so | |
| 3 | 2 | 6 | 3 | 8 | 5 | 1 | 4 | 9 | #4 MUST go in Cell D8, & therefore #7 MUST go in Cell E8 | ||
| 4 | 6 | 8 | 4 | 2 | 1 | 7 | 3 | 9 | 5 | ||
| 5 | 9 | 1 | 5 | 3 | 6 | 4 | 7 | 2 | 8 | ||
| 6 | 3 | 2 | 7 | 5 | 9 | 8 | 4 | 1 | 6 | ||
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | ||
| 8 | 8 | 5 | 9 | 4 | 7 | 1 | 6 | 3 | 2 | ||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 4 | 7 | 8 | 1 | 2 | 9 | 5 | 6 | 3 | Step 30: Complete Column D: #7 MUST go in Cell D3… | |
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | ||
| 3 | 2 | 6 | 3 | 7 | 8 | 5 | 1 | 4 | 9 | Step 31: Complete Column E: #2 MUST go in Cell E1… | |
| 4 | 6 | 8 | 4 | 2 | 1 | 7 | 3 | 9 | 5 | ||
| 5 | 9 | 1 | 5 | 3 | 6 | 4 | 7 | 2 | 8 | Step 32: Complete Column F (and Row 1 & Block BB): | |
| 6 | 3 | 2 | 7 | 5 | 9 | 8 | 4 | 1 | 6 | #9 MUST go in Cell F1. | |
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | ||
| 8 | 8 | 5 | 9 | 4 | 7 | 1 | 6 | 3 | 2 | ||
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 4 | ||
| A | B | C | D | E | F | G | H | I | |||
| 1 | 4 | 7 | 8 | 1 | 2 | 9 | 5 | 6 | 3 | 45 | Final Proof: |
| 2 | 5 | 9 | 1 | 6 | 4 | 3 | 2 | 8 | 7 | 45 | - All Rows add up to 45; |
| 3 | 2 | 6 | 3 | 7 | 8 | 5 | 1 | 4 | 9 | 45 | |
| 4 | 6 | 8 | 4 | 2 | 1 | 7 | 3 | 9 | 5 | 45 | |
| 5 | 9 | 1 | 5 | 3 | 6 | 4 | 7 | 2 | 8 | 45 | |
| 6 | 3 | 2 | 7 | 5 | 9 | 8 | 4 | 1 | 6 | 45 | |
| 7 | 7 | 4 | 2 | 8 | 3 | 6 | 9 | 5 | 1 | 45 | |
| 8 | 8 | 5 | 9 | 4 | 7 | 1 | 6 | 3 | 2 | 45 | |
| 9 | 1 | 3 | 6 | 9 | 5 | 2 | 8 | 7 | 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 | |||||||||
Send your Comments to joe-ks.com