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Friday August 31, 2007

Math Questions

I was checking the answers in Duncan's 4th grade Math homework last night, and came across this question:

  Q. There were 15 problems on a math quiz. Keith missed two.
     How many problems did he get right?

To me, this all comes down to what exactly did they mean by "missed two"? Did he get those two wrong, or did he fail to complete them? For the former the answer is 13, for the latter, the answer is N.E.I (not enough information). It'll be interesting to see how his teacher marks it.

I used to hate questions like this. They should all be clear and completely understandable.

I suppose it could have been worst. At least it's better than these two:

  Q. Duncan has 2,678 Pokemon cards. He only needs 10 more to
     complete his first set. Each pack costs a dollar and
     contains 5 cards. How much does it cost to get that
     first set?

  A. $254. (You never gets the ones you want).

  Q. There are five crows sitting on a fence. The farmer gets
     out his shotgun and blows one away. How many crows are left?

  A. None. (Would you just sit there if someone was shooting at you?)

( Aug 31 2007, 08:14:30 AM PDT ) [Listen] Permalink Comments [8]

Comments:

I calculate the expected number of packs you'd need to buy as 1507 assuming that each of the 2,688 cards has a uniform probability of being in the pack. In actual practice, it's likely to be a good deal worse than that because the more rare cards will be the most likely to be not yet in the collection.

The variance unfortunately is also huge, so expect to shell out bug bucks to get those last few cards.

Posted by Rob Adams on August 31, 2007 at 01:28 PM PDT #

If there are 15 problems on a math quiz, knowing that Keith missed two doesn't tell us jack about the state of the other 13. Maybe after "missing" the first two, Keith concluded that the document in front of him was an inaccurate -- and hence unfair -- tool by which to judge mastery and decided to go for an early recess instead.

Posted by joanie on August 31, 2007 at 09:15 PM PDT #

3rd grade homework I assisted with last spring:

"Steve has $73. How many $10 notes does he have? How many $1 notes does he have?"

None, I told my kid. It's all in twenties, fives, and/or change. As is the money in the other three amounts given, all with the same questions attached.

Posted by Michael on September 01, 2007 at 09:24 AM PDT #

"Q. There are five crows sitting on a fence. The farmer gets out his shotgun and blows one away. How many crows are left?"

I am not usually one to fall over this but to me that seems like a very strange question for a kid. It might be that I am from Holland and using/owning/shooting guns is _not_ the norm, but maybe it is just the ambiguity of the question that bothers me most... :-)

PS Are that math questions you pose at the bottom before posting a comment there to prevent your kid from 'spamming' you...?

Posted by Roderik on September 03, 2007 at 01:39 AM PDT #

The last two questions are attempts at humor. I wouldn't expect to see them in a real math quiz.

Posted by Rich Burridge on September 03, 2007 at 02:55 AM PDT #

There is one cow left, the dead one, the 4 others left the scene.

Posted by Thomas Pedoussaut on September 03, 2007 at 05:48 AM PDT #

I'd like to know how those cows had been sitting on the fence in the first place.

Posted by Rich Burridge on September 03, 2007 at 09:14 AM PDT #

So what have we learned from all of this, boys and girls?

That math is a precise and logical area of study in which the "right" answer is not calculated as much as it is surmised by making assumptions about what some unseen authority expects you to answer. That providing a more precise and logical answer (i.e. N.E.I.) will cause you to be penalized. That math is most certainly NOT funny. That given sufficient time and motivation, you can accomplish what has been deemed impossible by the masses and do so in the face of great adversity (such as maintaining your balance on a fence that can't support your weight and do so even though you're top-heavy, exhausted from having spent all last night resisting the efforts of the intoxicated college students insistent upon tipping you, and have just been shot and abandoned by your friends). That if you press the "Comment Preview" button enough times, eventually you'll get a CAPTCHA that doesn't require "carrying the 1".

I suppose these are all important life lessons, but it does make reading seem like the more promising subject. ;-)

Posted by joanie on September 03, 2007 at 11:06 AM PDT #