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If we define the "subtraction score" to be the amount of times you can subtract the last letter of a word and have the result also be a word, what is the highest possible subtraction score for an english word? Proper nouns do not count.
Pluralising something is a good way to get an extra free point
Inks -> Ink -> In -> I (Score of 3)
Tablets -> Tablet -> Table (Score of 2)
Jealous (Score of 0)