Fun Facts are designed for, and work best in, lower-division college courses where the typical student is not a math student. The...

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## About Math Fun Facts

I developed Math Fun Facts in 1994 as a warm-up activity for the calculus courses I taught as a graduate...

Continue reading...## Multiplication by 111

If you liked the Fun Fact Multiplication by 11, you’ll enjoy seeing how to take that idea one step farther. Here’s...

Continue reading...## Liouville Numbers

Are there any real numbers that are NOT algebraic, i.e., expressible as the root of a non-zero polynomial with integer coefficients? In fact,...

Continue reading...## Dedekind Cuts of Rational Numbers

Given a number line with equally spaced tick marks one unit apart, we know how to measure rational lengths: the...

Continue reading...## Computability of Real Numbers

We can write a computer program that will successively print out the digits of the decimal expansion of Pi. We...

Continue reading...## Fermat’s Last Theorem

There are lots of Pythagorean triples; triples of whole numbers which satisfy:x2 + y2 = z2. But are there any which satisfyxn + yn =...

Continue reading...## Rationals Dense but Sparse

Well we all know that between any two real numbers there is a rational. Mathematicians like to say that the...

Continue reading...## Ordinal Numbers

One of the most useful properties of the whole numbers is that every non-empty subset has a least element; this...

Continue reading...## Risk-Free Betting on Different Beliefs

Alice believes that the 49ers will win the Super Bowl with probability 5/8. Bob believes that Ravens will win the...

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