It was a note of frustration and exasperation, written to her classmate and not meant to be taken literally. But it raises some questions that deserve better answers than are usually supplied.

"I just failed a chemistry test," the 11th grader wrote. "I'm so sick of learning worthless things and not understanding them, either. And I'm sick of parents who place your worth on your grades. Some letters on a piece of paper have nothing to do with ME!

"I've learned so much from chemistry. I just can't do the intimate details of the stuff. But I don't need to know that to get by in my life, anyway. And I certainly don't need to know how to find the sixth root of a negative reciprocal to the two- thousandth power. I'll do just fine in life without algebra and the picky calculations in chemistry.

"Why don't they teach us us something useful and important, like current events, or about the earth and the universe? I don't know what Vietnam was, but I can figure out (radical numbers).Big deal. And what about Beirut and Grenada? Kids our age were killed there, and no one teaches me about that! My mom can take this 20.5 chemistry grade and . . ."

You get the idea. Similar thoughts have been voiced by frustrated students at least since the ancient days when I was voicing some of them -- usually out of frustration over having failed to prove to the teacher's satisfaction that Angle A in some Jacob's ladder of a diagram was equal to Angle Q.

What difference did it make? Where was the practical utility of such arcane knowledge. In "real life," as we called it even then, the angles were either sufficiently close to the same maginitude as not to make any difference, or if I needed to know whether one was slightly larger, I could always measure them directly.

There were two standard answers. From parents: "You need to learn it in order to get a diploma." From teachers of geometry, chemistry or algebra, it was that this arcania "teaches you to think." But the first answer obviously begged the question of why such knowledge was necessary for graduation, and the second, it seemed to us, overlooked the fact that it involved such specialized thinking that any practical application was beyond imagining.

Are there better answers? I think so. There really is value in mental discipline, and in learning to reason along cold, analytical lines. Too many of us form opinions on the basis of emotion, of what we would like the outcome to be, rather than following the facts where they lead.

More important, though, is the fact that a solid grounding in math and science is a prerequisite for a growing number of careers. Lawyers need to think, not merely feel. Students of social science need enough math to enable them to handle statistics. Medical students need the basics of chemistry before they enter med school.

Too many young people, including a disproportionate number of women and minorities, discover too late that their career options are circumscribed because they took only the required courses in high school math and science.

The 11th grader is right. No high school student should be ignorant of the events in Nicaragua or El Salvador or South Africa, or fail to understand that the African famine involves more than a temporary food shortage, or imagine that the homelessness of the "street people" or the explosion of adolescent pregnancy are things that just happen.

But math and science are important, too. Even those who know with certainty that their careers will involve only the most rudimentary mathematical ability need to know "about the earth and the universe," as the young letter-writer put it. For those who haven't yet decided on their careers, whose career fields very likely don't even exist yet, the tougher math and science courses help them keep their options open.