8plus 3 equals 12.

Uh-uh. Try again.

8 plus 3 equals 11.

That's better. For that, you get a smiling, "happy face."

No teacher with a box of decals or gold stars is correcting this math problem. A computer is.

Not surprising, since computers are invading every nook and cranny of American society. Banks use them. Groceries use them. Even this story was printed with the aid of computers. And, in California, the newest summer camp for kids is two months of canoeing, camping and -- you guessed it -- computers.

Beginning this week, Alexandria elementary schools will join the revolution in a computer-calculator program for fifth and sixth graders.

In the program, sixth graders will get a minicourse on computer basics -- the special language of computers, how computers work and how to operate a computer. As an appetizer for what's to come, fifth graders will get a minicourse on hand-held calculators.

Some sutdents already have tested the course, in an experimental program at Douglas MacArthur and George Mason elementary schools. Teachers were delighted with the response, and students were so taken with the course that many gave up after-school time to "play" with the computers.

The excitement about the program seems to have pervaded all levels of the school system. When asked about the program recently, Donald D. Dearborn, assistant superintendent for elementary and secondary education, insisted on personally demonstrating the new system.

First, there are basic math problems, the kind sixth-graders will get a chance to solve on a microcomputer, which looks much like a television attached to an electric typewriter keyboard.

Students also can play games -- backgammon, checkers, black jack -- designed to sharpen skills in deductive reasoning and basic mathematics. But the computers were purchased, at a discount of $710 each, for other reasons.

"We're trying to develop an appreciation for the role and function the computer plays in society and to get away from the mystique surrounding computers," Dearborn said, obviously having as much fun as a 10-year-old as he punched the buttons on a computer keyboard to call up problems in addition, subtraction, multiplication, and division.

Dearborn, like the teachers who have conducted the experimental math and computers classes, emphasizes that the computers are not designed to replace the teaching of basic skills. Rather, he says, computers are an aid that can enhance learning and make it fun.

"We aren't trying to make junior programers out of (the children)," Dearborn says. "We're using this as an instructional math tool."

Adds Miriam Etris, who taught computer calculator classes in the pilot program at MacArthur, "It is the responsibility of the teacher to teach math skills. We should never consider allowing children to use them as a crutch. The computer is an aid to learning. It can't do things by itself."

Alexandria's program follows a trend in many schools to introduce students to computers. The National Council of Teachers of Mathematics, in its recommendations for the 1980s, urges school systems to integrate the use of computers and calculators in basic mathematics programs at all levels, and computer firms are busily turning out curriculum programs to meet the growing demand.

"Its's important to the future of society that we start (children) young with computers, literally because their lives are going to be so involved in it," said Gail Kahn, who taught computer and calculator courses at George Mason last year.

Alexandria already has more advanced computer courses for junior and senior high students, who can take the classes as electives.

The junior high program was designed by George Washington teacher Mary Sue Garner, who developed a course to teach teachers about computers. In fact, Dearborn noted, the junior program has been such a success that 500 students are enrolled this year, more than twice the 240 enrolled last year.

Alexandria will have 50 microcomputers and 180 calculators for its elementary program and 40 computers for the junior highs. The elementary grade computers will be moved from school to school as each sixth grade class completes its four-part course.

A few computers will be left at each school so children can continue to use them.

Alexandria also is making sure that its pioneering efforts will benefit all students.

"There will be a computer for every child (in the classroom) so we won't have one child on the keyboard and two or three watching," Dearborn said. "we don't want to have a situation where a child says, 'I'm not good in math, so I'll just watch while Johnny does the problem.'"

Teachers who worked in the experimental program have no doubts that the new course will be a success.

"(Students) . . . see the results on the (computers) screen immediately, so they're thrilled," said Etris. "They're seeing something concrete, learning that all this means something. It's like going to France and hearing people speak French. All of it (the studying) comes together."