Meet Aaron Chow

Dr. Chow is very excited to be joining your class. You can use the information below to prepare for our visit.

Teacher Resources

Dr. Chow will be speaking on Cryptography and Banking in his talk.

Below are a few concepts you should review with your students prior to the talk if possible.

There are also a few videos you can show your students as well!


If you are, able please provide a copy of the following handout to your students to try prior to the visit. The handout deals with modular arithmetic so you may want to watch the below video with your class prior to trying it out.


Modular Arithmetic

Prime Numbers


These are the whole numbers that evenly divide a number. For example:

    • the factors of 8 are 2 and 4
    • the factors of 12 are 2, 3, 4 and 6
    • the factors of 25 (a square number) is 5
    • 13 has no factors, so it is a prime number

Prime Factorization

This is the unique set of prime numbers that make up any other number. For example, the prime factorization of 8 is 2 x 2 x 2.

A prime factorization is made up of only prime numbers, multiplied together. The factors of 18 are 2, 3, 6, and 9. However, the prime factorization of 18 is 2 x 3 x 3 (as we are only using prime numbers, of which 6 and 9 are not).

Every number can be written as a unique combination of prime factors. You can explore these more here as well: (under Prime Factor Circles and Dot Arrangements)

The reason 1 is excluded as a prime number (and therefore in the prime factorizations) is because, if we include it, we can no longer write numbers as UNIQUE products of primes.

For example we could write 8 = 2 x 2 x 2 OR 8 = 2 x 2 x 2 x 1 OR 8 = 2 x 2 x 2 x 1 x 1

Since multiplying by 1 doesn’t change the number we could add as many 1’s as we wanted, so there would no longer be a single unique representation of each number.

So we write our definition of a prime number to exclude 1 from being prime in the first place so we don’t have this issue.