May 26, 1994|By Sherry Joe | Sherry Joe,Sun Staff Writer

It stands 4 feet tall, is built of 80 triangles and 12 pentagons, and is covered with mathematical equations, definitions and questions.

And according to the students at Longfellow Elementary School who built it, the strange geometric form is the world's largest "snub icosidodecahedron," the mathematical term for a many-faced structure made of pentagons and triangles that looks something like a soccer ball.

Fourth- and fifth-grade students in the Columbia school's gifted and talented math program made the shape yesterday, guided by Dr. S. Brent Morris, a mathematician at the National Security Agency in Fort Meade, and his assistant, Jamie Met, a student at Virginia Tech.

"This is just sheer exuberant mental exercise," said Dr. Morris, who wants to inspire in the children a lifelong love of math. "Any subject can just put you to sleep if you don't express excitement and enthusiasm to students."

Creating shapes helps students learn geometry, problem-solving skills and teamwork, said Kimberly Kinner, Longfellow Elementary School's gifted and talented resource teacher.

"This teaches them something they can't get out of a textbook," Ms. Kinner said.

Last year, Dr. Morris helped some of the same students create a ball-like form that mathematicians call a "rhombicosidodecahedron," built of squares, triangles and pentagons.

Before the students began assembling their latest geometric creation, Dr. Morris demonstrated the shapes they would need, using small plastic interlocking triangles and pentagons.

The students used pipe cleaners to hold their own poster board triangles and pentagons together, bending the shapes into the form of a giant ball.

Earlier in the year, the students had decorated the shapes with algebraic equations, and questions, such as "How many sides are there in a cube?" and definitions, such as "A triangle is a polygon that has three sides."

"It's fun," said Bona Kim, a 10-year-old fourth-grader. "It's a group project, and while you're learning math you can have fun."

The shape-building exercise is part of an effort to keep younger students interested in math through nontraditional teaching techniques. In class students sometimes write stories using numbers and sing songs that feature mathematical rules.

Such approaches to math instruction are important, Dr. Morris said, whose two children graduated from Longfellow.

So much emphasis is placed on learning basic skills such as addition and subtraction "that the fun of experimenting and fun of learning is missed," he said.