NIU math professor Richard Blecksmith brought audience members back to grade-school mathematics in his lecture about prime numbers, “Galaxies of Prime.”

The lecture, hosted by the Institute for Learning in Retirement (ILR), took place Wednesday at the Campus Life Building. The ILR is a campus-based program that has about 110 members who are retired faculty and community members, said Steven Johnson, director of External Programming.

Blecksmith said he has spent his whole life working with prime numbers, and he wanted to convince his audience that prime numbers are “pretty cool.”

He was happy to see more than 25 people who showed up to hear the lecture. Blecksmith said that learning doesn’t end when you get your high school diploma or even when you get a Ph.D.

His lecture began by reviewing some basic math concepts and simple math problems. One example he gave compared the solution his daughter’s fifth-grade textbook gave and his own version of the solution.

“I think my solution is a little easier to follow,” Blecksmith said.

Another example he gave contained a number that had 51,000 digits. In order to write that number out, he would have needed 200 overhead transparencies. He put the number in exponential form.

Blecksmith also spoke about the importance of understanding prime numbers in relation to encrypting security codes. He said that modern-day security systems all use prime numbers.

Johnson said that he found this part of the lecture very fascinating. He enjoyed how Blecksmith established a relationship between prime numbers and something that is a part of normal life.