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In a tracing puzzle, you canâ€™t lift your writing tool or go over a segment twice. This triangle is impossible, but is tracing it impossible, too?

In multi-level mobiles, weights on one level can affect another. Can you salvage this mobile, or is it unavoidably unbalanced?

Similar triangles can often hide in unexpected places. Could they help with this challenge?

With some reasoning, you can find a shortcut for the final digit of this multiplication problem.

Finding the probability of a single die roll is pretty simple. But what happens when more than one die is involved?

This cryptogram has multiple solutions, but that doesn't mean every digit changes in every solution. Which digits never change?

Two far-off lights appear to be the same brightness. But after moving closer, one now appears brighter. Which one is actually brighter?

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