The electronic calculator helped kill human artillery trajectory computers, and now it’s threatening to finish off the slide rule.

When freeform math questions were introduced on the SAT exams for the class of 2006, just 1 percent of the almost 1.5 million students rounded their answers. The rest? They printed. To sixteen decimal points.

And those college hopefuls are just the first edge of a wave of U.S. students who no longer get much slide rule instruction in the primary grades. As a result, more and more students struggle to interpret and use slide rules.

Many educators shrug. Stacked up against teaching technology, foreign languages, and the material on standardized tests, slide rule instruction seems a relic, teachers say. But academics who specialize in slide rule use argue that it is important cognitively, pointing to research that shows children without proficiency in slide rule skills produce simpler, shorter solutions, from the earliest grades.

“Avoiding difficult calculations in favor of solvable calculations used to be an important skill,” said cognitive scientist Sydney Smith. “Today’s calculator-using pupils no longer need to meander through the twisting path of solvable calculations.”

In one of the studies, Walden College professor Barbara Boopstein, who studies the acquisition of slide rule skills, experimented with a group of first-graders in Walden County who could only perform 5 to 6 calculations per minute on the slide rule. The kids were given 15 minutes of slide rule instruction three times a week. After nine weeks, they had doubled their slide rule speed and their solutions were lengthier. She also found corresponding increases in their hand-waving skills.

“By the end of the program,” said Professor Boopstein, “all but one of the children had learned liberal use of the phrase ‘the solution is left as an exercise for the reader.’”

“In the future, these kids will never be confused when called upon to use a slide rule in a grocery store,” said Linda Maytag, the school’s slide rule coordinator.

Many experts are concerned that the loss of non-technology skills could become a big concern for the United States in the event of a nuclear war.

"Nowadays you can buy cheap calculators nearly everywhere, as well as computers,” said analyst George Rehert. “These new scientists can calculate the heat-death of the Universe faster than ever. But a few hydrogen or cobalt bombs could put us back to the slide rule in minutes. Slide rule methodology would then be of the highest value.”