I taught two sections of this course in Fall 2018 and one section in Spring 2017. Each section had 20 students.

The course covered basic arithmetic problems and base-systems, diagram-based arithmetic algorithms (chip model, box model, etc.), algebraic manipulations (properties of real numbers, dealing with exponentials), number theory (modular arithmetic, divisibility criteria, factorials, theorem and proof of prime factorization, Euclidean algorithm), ratios and percents, real number representation, irrational numbers (proof that $\sqrt{2}$ is irrational). The course emphasizes mathematical rigor and includes proofs by diagram and by contradiction.

I was in charge of writing the exams, too.

Below you can see some sample material I wrote for this course.