In the rush to cover standards and ensure students have learned the concepts they will need in the future, it's easy to lose sight of how fun math can be. These three TED-Ed videos offer fun, challenging riddles that can also be explicitly connected to mathematical concepts. The "Prisoner Box" problem is essentially a loop and could be a high-interest way to dive into this topic.
In this next puzzle, viewers are cast as intrepid secret spies, tasked with deactivating a death ray. It's also an interesting introduction to visual models and graph theory. The answer explanation starts at 1:04 in the video.
Who can resist trying to solve a brain teaser that Albert Einstein supposedly wrote? This problem seems pretty complicated at first, but it could be a great way to give students an opportunity to sift through the information given and start making sense of it. The video explicitly talks about some effective problem solving strategies like trial and error that can help students develop their logical intuition. And, while this is a silly problem about a stolen fish, multiple variable equations require a similar type of logic.