## Facebook + Math

I’m feeling that lately there is an uptick in the number of order of operations quizzes on Facebook like the one above. Is anyone else feeling like that? Or, maybe I just have crazy friends?

### 5 comments

1. I’ve noticed that, too. And many of them are designed specifically to trick people by taking advantage of the ambiguity of the slash mark as a division sign: Does it act as a simple division symbol, or does it make a fraction with everything after itself (at least, all the multiplied terms) a denominator.

My daughter says it’s like the little kid who asks, “What’s 1 + 1?” If you say “2″, then the kid says, “No, silly, it’s 11!” But if you say “11″ then you’re really stupid.

In both cases, the question is designed to let the person who asks feel smarter than anyone who answers it.

2. Yes, I’m always interested in what makes a “good” problem. These in virtue of the number of times they are answered/reposted have some allure for people. I think for these problems it is the fact that the math is totally unintimidating. Everyone thinks, “I’ve got this.” And then they see so much disagreement about what they think is obvious. A lot of iPhone games take this approach of an insanely easy entry to the game, yet as you play it you recognize a subtlety in the game. I once posed a questions to get readers to use an alternate order of operations and am suddenly reminded of it. Thanks for the comment.
http://www.yofx.org/?p=1624

3. I’ve actually had students come in with these facebook questions. Students who didn’t seem to put in much effort in my class, but who were determined when math was made into a contest. I know Sue mentioned this phenomenon before, but it’s very true. Either way, I want your opinion on this. This came from a 4th grader whose parent I’m friends with. The 4th grader and I came up with the same answer while Jill and the parents came up with another. Let me know what you get:

Solve:
(27 – 11) / 2(x – 10) = 4

The / is actually the obelus (รท) but I’m not sure the symbol would show up. (And since this was 4th grade is was a blank box not an ‘x’)

4. I got 10.5. I’m guessing the difference in your answers hinges on whether you interpret the (x-10) to be in the numerator or denominator. I think technically it should be in the numerator. Although the spacing (which isn’t really a part of the order of opps) makes it very tempting to put below.

5. I got the same answer of 10.5 as well.