1: Not in USD.
2: 8?
3: None, it's a hole.
4: 1.
5: ?
6: There are more than three rungs.
7: Because human said so.

8: 5.5, if the order of operations is followed.
9: Take your pick.

10: Neither. Blackboards are black.
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PS: Since these are trick questions, I know I got some wrong, if not all!
