Stretch your brain with 100 Numerical Games. The mind-bending puzzles will provide hours of fun as you put your brain to the test. They're great practice for improving your logical thinking and math scores. You may be a genius and not even know it.
Books can be attributed to "Unknown" when the author or editor (as applicable) is not known and cannot be discovered. If at all possible, list at least one actual author or editor for a book instead of using "Unknown".
Books whose authorship is purposefully withheld should be attributed instead to Anonymous.