A few weeks ago, responding to President Obama's suggestion that primary and secondary education could be improved by extending the school day and/or year, I mentioned that my 5-year-old daughter's elementary school has her for seven hours a day but still gives her homework. Several commenters agreed that homework in kindergarten is excessive, while others thought there are sound pedagogical reasons for it. I confess that the homework generally does not take much time, but sometimes it's very annoying. Right now, for instance, my daughter is learning how to count things with tally marks and convert the marks to numerals. Her first three assignments were pretty straightforward: She had to count all the doors, all the windows, and all the shoes in our house. But we didn't know what to do with the latest assignment: "Count the books in your house." The answer space allows only a two-digit number, so anyone with more than 99 books is out of luck. As we discovered, there are a few hundred books in my daughter's bedroom and several thousand in the house.

The assignment, which was copied from a worksheet book and therefore presumably is used at many other schools, seemed obviously unreasonable to me. Not only doesn't the answer fit in the space allotted (where you're supposed to put the number of tally-set pairs in the "tens" box and the number of remaining tally marks in the "ones" box), but the only practical way to complete the worksheet is to count the books on every shelf, add them all together, and translate the resulting total into tally marksâ€”the opposite of what you're supposed to do. Fitting all those tiny tally marks into the rectangle on the page is difficult for an adult, let alone a 5-year-old. And what sort of message are schools sending about the value of reading when they assume no one will have more than two or three shelves of books?

Upon reflection, however, I had no idea how many books the typical American household has. (I didn't even know how many we had until we counted them.) Could it be reasonable to expect no more than 99? The answer is surprisingly hard to find. Data from the 2000 National Survey on Childhood Health indicate an average of 83 children's books in white households (the corresponding numbers for black and Hispanic households were 41 and 33, respectively). I assume adults would tend to have more books than children (although maybe I'm wrong about that), in which case the average would be well above 100. In 2005, according to the Book Industry Study Group, 3.1 billion books were sold in the U.S., about 28 per household. Even allowing for institutional use and books sold, given away, or thrown out after the initial purchase, wouldn't more than 100 accumulate in the average household over, say, a decade? If you have information that would illuminate the issue, let me know in the comments. Also feel free to share your frustrating homework stories.