In ‘648’ and ‘756’ there is 6 in common, and ‘is’ is common in ‘met is wet’ and ‘floor is dry’ so “is” = 6. In ‘648’ and ‘987’ there is 8 in common, and “wet” is common in ‘met is wet’ and‘wet or dry’ so “wet”= 8. In ‘756’ and ‘987’ there is 7 in common, and “dry”is common in ‘floor is dry’ and ‘wet or dry’ so “dry”= 7. ∴ In 987, 8 = “wet” and 7 = “dry” , then 9 would mean “or”