Current Event:

Some (mathematically inclined) people celebrate March 14 as Pi Day. The numerical designation of the date–3/14–coincides with the first digits of the number pi, the ratio of a circle’s circumference to its diameter. Pi, also written as the Greek letter of the same name, π, is approximately equal to 3.14. It is a fundamentally important number in mathematics that is used to find the areas of circles and the volumes of spheres and cones. The ancients, notably the Greeks, had some idea that the ratio of a circle’s circumference to its diameter was a special quantity. The Greek mathematician Archimedes used geometry to approximate pi as the fraction 22/7.

Pi Day has its roots in the San Francisco Exploratorium museum, which has celebrated the holiday since 1988. As it happens, March 14 is also the birthday of the German-born American physicist Albert Einstein, who used pi in his famous equations for general relativity. Some people enjoy memorizing the digits in pi. According to the Guinness Book of World Records, the current champion is Chao Lu of China, who recited pi from memory to 67,890 places.

Archimedes was a mathematician and inventor of ancient Greece. He approximated pi as the fraction 22/7. (Granger Collection)

Albert Einstein was a German-born physicist. He used pi in his famous equations for general relativity. (© Hulton/Archive)

Objective:

Mathematics is one of the most useful and fascinating divisions of human knowledge. It includes many topics of study. For this reason, the term “mathematics” is difficult to define. Most of the basic mathematics taught in school involves the study of number, quantity, form, and relations. Nearly every part of our lives involves mathematics, and it has played an essential role in the development of modern technology. The work of mathematicians may be divided into pure mathematics and applied mathematics. Pure mathematics seeks to advance mathematical knowledge for its own sake rather than for any immediate practical use. Applied mathematics seeks to develop mathematical techniques for use in science and other fields. Mathematics has many branches, including algebra, arithmetic, calculus, geometry, probability and statistics, set theory, and trigonometry. The Behind the Headlines news story and related World Book articles explore various mathematical topics.

Words to know:

• Albert Einstein
• Archimedes
• Calculus
• Circle
• Circumference
• Cone
• Diameter
• Geometry
• Mathematics
• Pi
• Ratio
• Sphere

Discussion Topics:

1. Ask your students to debate, “Students should be required to take math all four years in high school.”

2. Ask your students to debate, “Many people think that it is OK to be bad at math.”

3. Ask your students to debate, “Because math and science teachers are in great demand, they should receive higher pay than other teachers.”

4. Ask your students to use World Book’s Timelines feature to view or add to the History of Mathematics timeline and the Albert Einstein timeline.