Number and Quantity
Pro Problems > Math > Number and QuantityFeatured Pro Problems

Without a calculator find a nine digit number that meets the criteria of the problem

Strings of red lights and green lights on my Christmas tree - a Christmas word problem
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The Value of a Word, Trick-or-Treat Math, Two NumbersUnderstanding Coronavirus Spread
A Question and Answer session with Professor Puzzler about the math behind infection spread.
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