Initial Domain : { 1,2,3,4,5,6,7,8,9 } Values in Box : { 2,8,9 } Pruned Domain After Checking Box : { 1,3,4,5,6,7 } Values in Column : { 2,3,4,5,6,9 } Pruned Domain After Checking Column : { 1,7 } Values in Row : { 7,8 } Pruned Domain After Checking Row : { 1 }(Edited: 2022-10-05)
We can remove 9,2,8 for the box. 7 can be removed for the row. 6,4,5,3 can be removed for the col. So the only remaining item is 1. Answer for E7 is 1
{1,2,3,4,5,6,7,8,9} Remove contraints in the box 2,8,9 {1,3,4,5,6,7} Remove contraints in the column 2,3,4,5,6,9 {1,7} Remove contraints in the row 4,7,8 {1} E7 = 1(Edited: 2022-10-05)