Question The four puzzle pieces in the image fit into the 4×4 grid without rotation or reflection. Based on these clues, find

Question The fuel used to propel spaceships can’t depend on atmospheric oxygen as a reactant, since they might not be operat

Question Your twin leaves you on Earth and flies away at 0.8c0.8c0.8c, then turns around nearly instantaneously and returns at the

Question Angles of the same color have the same measure. What is the measure of the green angle? 30° 35° 40° 45°

Question A young mouse is weighing an important decision.   The sound of human footsteps is approaching, and the mouse needs

Question How many squares in this grid contain the orange square? 14, 18, 19, 55  

Question Each letter stands for a distinct digit, and if letters are different, so are the digits they represent. What digit is E?

Two trains, each traveling at a speed of are headed toward each other on the same track. At the exact moment the trains are apart,

Art gallery problems involve finding an unmoving guard (or guards) who can “see” the entire gallery. A guard is able t

Can Area Reveal Volume? Consider the two shapes inside the two identical cylinders whose radius is equal to its height.

Can a 10 x 10 grid of cells be covered by 25 1 x 4 pieces?

All four Kings from a deck of cars are placed face down on a table in a random order. You select two of them, and if both are the