Can you solve the feeding frenzy riddle? - Henri Picciotto
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As Numberland’s best detective, you thought you’d seen it all. But the desiccated corpses of prominent natural numbers have been showing up all over the city. A lockdown is ordered from sundown to sunrise, and it’s still not enough to stop what can only be described as a vampiric feeding frenzy. Can you figure out why the citizens of Numberland are being attacked? Henri Picciotto shows how.
Additional Resources for you to Explore
Slime numbers are numbers that can be sliced into a sequence of primes.
For example, 41 (which is already prime), or 41075 → 41|07|5. Explore slime numbers in this worksheet (It is excerpted from the materials in Henri Picciotto’s Infinity, an elective high school math course).
When thinking about whole numbers, it is convenient to quickly recognize multiples of certain numbers. (For example, all multiples of 5 end in 0 or 5.) Wikipedia has a big list of divisibility tests.
Want more puzzles? TED-Ed has lots of fun and challenging brainteasers in our Riddle Series!
For example, 41 (which is already prime), or 41075 → 41|07|5. Explore slime numbers in this worksheet (It is excerpted from the materials in Henri Picciotto’s Infinity, an elective high school math course).
When thinking about whole numbers, it is convenient to quickly recognize multiples of certain numbers. (For example, all multiples of 5 end in 0 or 5.) Wikipedia has a big list of divisibility tests.
Want more puzzles? TED-Ed has lots of fun and challenging brainteasers in our Riddle Series!

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