In Very Good Condition 
 
Derrick Niederman, one of Sterling's most popular puzzle authors, has come up with another collection of super-tricky math brainteasers that's great for home or the classroom. Hours of mind-bending, brain-stretching fun await solvers, who can warm up with easy problems like this, before moving on to harder and harder conundrums: "Hector can run from the train station to his parents' house in eight minutes. His younger brother Darius can run the same distance eight times in one hour. Who is faster? Some of the puzzles present visual patterns to interpret, or play tricks with multiplication and division. Every one will give the brain a good workout, and improve math skills in the most enjoyable way. (Answer (small and upside down): "Darius. It would take Hector 64 minutes to run the same distance Darius can in an hour.)