... by: Frans Goosens

#660

Combination 2-digits cells

A5=8 No solution, Undo calculation
A5=9 Wrong, Undo calculation
A5=8 No solution, Fixed
A8=1 ( D6=8 ) Solved,

Total solving time is : 42 sec.
Number of logical steps is : 4816

... by: Envy E

Once 6 & 9 have been removed from C1 C3

Set C1 to 5

Following the logic of my previous posts leads to +8 E1 +9 H5 +6 J9 +5 H1

5 removed from C1

C1 set to 7 & C3 set to 5 gives a solvable puzzle

... by: Dieter

#660 - initially populated cells: 23 = 28,4%
No solver used.
basics: D5=4
populated cells: 24 = 29,6%
Strategy:
Step 1: Number 4 occurs most frequently; 2 cases: B1=4 or B2=4
Step 2: numbers 2,3,7 occur most frequently, combine two cells:
combinations of C6 = (1,2,3) and G6 = (3,5,7)
B2=4 solves with C6/G6 = 1/5

Review:
C6=1 & G6=5 solve.

... by: Envy E

Same strategy as previous comment works for -5 C3 +5 C1 ( +7 A2 C9 )

6 & 9 eliminated from C3

... by: Envy E

-7 C1 ( +7 A2 +2 A3 [ +1 A8 A9 ] +2 F2 [ +3 E2 E3 ] +2 D8 +2 J7 [ +1 E7 F7 ] +2 H4 [ +7 G4 G6 ] +2 C6 )

+7 C9 +3 B8 +3 F9 +568 E8 F8 +56 G8 +7 H8 +1 A8 +9 A9 ( +6 C7 ) +8 A5 +1 B6 +9 C4

6 & 9 eliminated from C1

... by: Serban

# 660 D5=4 Basics to 24
1. Number 7 n=3 e=6 N=18 Nc=11 Ns=7 => F2=H4=7 basics to 36
1a.X-chain x=8 => [J1,EHJ5,B6,A8]<>8 => A5=8 solve

2. Number 8 n=2 e=7 N=27 Nc=26 Ns=6 => B8=F1=8 solve
correction !!
1. Number 1 n=2 e=7 N=30 Nc=69 Ns=40 =>
1a. J7 = F9=1 solve
1b. J7 = B3=1 solve
1c. J7=1 basics to 32 X-chain x=8 => [EHJ5,B6,A8]<>8 => A5=8 solve

... by: Dieter

#660 - initially populated cells: 23 = 28,4%
No solver used.
basics: D5=4
populated cells: 24 = 29,6%
Strategy: Numbers 2,3,4,7 occur most frequently, combine two cells.
combinations of G7 = (4,6) and H8 = (1,2,5,6,7)
4 matrices remain after basic checks: G7/H8 = 4/1, 4/2, 6/2 and 4/7
G7/H8 = 4/2 solves with A3=9

Review:
A3=9 & H8 = 2 solve.

... by: Serban

# 660 D5=4 Basics to 24

1. Number 1 n=2 e=7 N=30 Nc=69 Ns=40 => F9=1 solve

2. Number 2 n=3 e=6 N=14 Nc=4 Ns=1 => J6=2 basics to 33
2a. X-chain x=8 => [EF4,FHJ5,B6,H8]<>8 => A5=8 solve

3 Number 5 n=2 e=7 N=32 Nc=38 Ns=36 => D8=5 solve

4. Number 9 n=2 e=7 N=29 Nc=38 Ns=36 => A3=H1=9 solv



Note: C3=5

... by: Yves

A2=2 F8=3 Solve