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<p>This is not restricted to k-12 math.
When S took a college physics class (while in high school), he received back comments on his problem set: “Even in physics, we use English, you know.”
It seemed that “since” and “therefore” were not adequate explanations.</p>
<p>The most valuable part of the AP-Calc test is the Free Response Question where students are asked to explain their solutions (as opposed to multiple choice). They do get partial credit for right explanations even if the computation leads them astray. </p>
<p>I don’t mind a certain amount of writing in math; done well, it can illuminate what the actual problem is that needs solving (it’s amazing how many students charge ahead without asking themselves what the writing prompt–even in the form of a question–really seeks to elicit, even in the social sciences and humanities, let along math or science). However, sometimes, the writing is totally irrelevant to actual math learning.</p>
<p>Sometimes, the question can be fuzzy and trip students. A classic example is that of the 136 soldiers who need to be ferried to some exercise spot by bus. Each bus can carry 42 people. How many buses are needed? This problem was presented to parents when the high stakes tests were first introduced (they were then presented as diagnostic tests, rather than as high stakes ones). The DOE representative said that either 3 buses, or 3 buses with a minivan to ferry the remaining 10 soldiers would be an acceptable answer.
The fact is the question was fuzzy. Was it really to test the students’ knowledge of division? In which case, 3 buses, (leaving 10 soldiers stranded) would be okay. Or was it a question about how to get all the soldiers to the exercise field? In which case, something had to be done to get the remaining 10 soldiers to the field. A parent pointed out that if the question had been about transporting 136 students to a game or a picnic, the students would have unerringly figured out that it was not okay to leave 10 students behind, and would have answered 3 buses and a minivan.</p>
<p>Of course, the question can be simply posed as “Divide 136 by 3.” But then, there are many students who do not know when a particular computation is needed, though they do know their mulitplication facts and their long divisions.</p>