470: Poor Alex Bellos

Normally, I'm glad when the nedia talks about math, even if it is simply the latest "Super-Hard problem from Asia that All of Us Stupid American Adults and Brits Won't be Able to Solve but Their 8 Year-old Do Routinely."

Throw in "I gave it to a mathematician and he couldn't solve it either" and you've got an instant viral hit, apparently.

All right, rant over.

What's the error?

Oh, and solve it if you want, too. It's not really that hard.

Further questions:

• Which blanks CANNOT have a prime number in them?
• Which blanks COULD have certain prime numbers?
• Which blanks essentially force this problem to be non-unique?

source.
(answer linked from there)

393: Numbers or Percents

This graph is not distorted, but interpretations of it may jump to wrong conclusions.

• What incorrect conclusions might be drawn?
• If a person with a bias against public school funding were to interpret this, how might he do so?
• Would you fix the graph? If so, how would you change it?

Source, from this page.

277: Central Tendency Mistakes

Expand that image to see details. As you peruse the list of values, how far can you get before you reach an inconsistency? Can we figure out what date each of the five pennies showed?

If you knew this was from a college teacher-education professor, would this change your opinion of the work shown in the picture?

236: Make the area Unique

Can we solve for area? If not, what different additional information could be added?

13: Strange Triangles

Triangle ABC is congruent to triangle DEF.
In triangle ABC, side AB measures 9, side BC measures 3x+18, and side CA measures 7.
In triangle DEF, side DE measures 9, side EF measures 2x+26, and side FD measures 7.

What equation would help you to solve for the side length of BC and EF?

(Actual question in an on-line geometry course.)

What would you do to fix this question?