Introduction to Clock Arithmetic and Modular Systems

Most of us are familiar with 12-hour analog clocks. They are numbered 1 through 12; they have hour, minute, and second hands. In this post, we are going to experiment clock arithmetic — we are going to perform addition using the numbers on the clock.

clock arithmetic

Let us think about the following questions.

  • What if we add 3 hours after 8:00?
  • What if we add 2 hours after 3:00?
  • What if we add 4 hours after 11:00? » Read more