SOLUTION: I cant find the logic. 1515=0, 1670=2, 1681=3, 1899=4, 1989=?

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Question 936008: I cant find the logic.
1515=0,
1670=2,
1681=3,
1899=4,
1989=?
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
This is one of those overused trick/logic problems -- the answer is equal to the number of "holes" when writing out the number out (e.g. every 4, 6, or 9 has one hole, every 8 has two holes). Hence the answer is 4.