# Solving an "Unsolvable" Math Problem

Until recently, there were just 14 known convex pentagons (nonregular, five-sided shapes with outward-pointing angles) that could “tile the plane” (be arranged with flush sides on a flat surface, with no gaps or overlaps). But last month, some thirty years since the 14th was discovered, a 15th was identified.

# Can You Outwit Tens of Thousands of *New York Times* Readers?

Here’s a fantastic exercise in thinking about thinking: *The Upshot* at the *NYT* is hosting an interactive puzzle that pits you against **every other person who attempts the puzzle**. It’s... a bit of a mind game.

‘They will never make a movie about him. He doesn’t have a troubled life. He has a family, and they seem happy, and he’s usually smiling.’’ A student describes the “super normal” Terry Tao, one of the world’s greatest mathematicians, in a recent *NYT Mag* longread, which, ICYMI, is outstanding. Read it here.

# Can You Solve Isaac Newton's Tree Puzzle?

This week’s puzzle is not about gravity, though you’d be excused for suspecting as much. After all, when most people read “Isaac Newton” and “tree” in the same sentence, they think also of falling apples. But this week’s puzzle, which is widely attributed to Newton, is actually an exercise in orderly arboriculture.

# U.S. Wins International Math Olympiad for First Time In 21 Years

For the first time since 1994, a team of top-tier mathematics students from around the United States has taken first place at the International Mathematical Olympiad, a global competition that this year included teams from more than 100 countries.

*How to Bake Pi* Uses Math to Solve the Cookbook Paradox

There is a lie running through your cookbooks. No, it’s not that you can substitute crackers for apples in your pie and no one will know the difference (though, come on, let’s be decent to each other, folks: Knock that off.) The lie goes much deeper than all that, and is the source of what I call the Cookbook Paradox.

# A Dastardly Application of the Prisoner's Dilemma

The following “opportunity” appears in a survey posted on a University of Maryland domain. We don’t know what class this problem was intended for (given its nature, we’d guess maths, econ, or psych). What we do know is we like this teacher’s style.

# Why Cooking Is A Lot Like Mathematics

I’ve come to believe that mathematics, as an investigative science, as a practical discipline and as a creative art, shares many characteristics with cookery. It’s not just spaghetti alla carbonara, it’s the whole business of inventing dishes and preparing them. It’s an analogy with many parts, and it has consequences.

# A Little Number Theory Makes The Times Table A Thing Of Beauty

Most people will probably remember the times tables from primary school quizzes. There might be patterns in some of them (the simple doubling of the 2 times table) but others you just learnt by rote. And it was never quite clear just why it was necessary to know what 7 x 9 is off the top of your head.

# The Whys, Wherefores, and Wonders of Mathematics

Check out this delightful video of math teacher Paul Lockhart—author of *Measurement, "*a permanent solution to math phobia by introducing us to mathematics as an artful way of thinking and living"—waxing lyrical about the splendors of mathematics and mathematical thinking, and why "the mathematical question is always…

# Can You Solve the Math Problem That Has Torn Singapore Apart?

A question on a quiz for teenage mathletes proved so tricky for Singapore newscaster Kenneth Kong that he posted it to Facebook to find a definitive answer. Now the problem has driven the entire country mad, and it's spreading to the rest of the world.

**How long would it take to fall through Earth? **For years, physics students have been told the answer is 42 minutes. But a new calculation, published in the latest issue of *The American Journal of Physics*, gives a more accurate travel time of 38 minutes. Over at *Science*, Adrian Cho unpacks the new equation.

# This Week's Puzzle Is Impossible. Can You Explain Why?

The solution to this classic puzzle is that it's impossible to solve. But can you explain *why* it's impossible?