Cryptarithms and Other Arithmetic Puzzles

Author: Sian Zelbo

Sian Zelbo was a practicing lawyer when she decided to return to school to explore her latent interest in mathematics. Sian studied mathematics and later mathematics education, eventually earning her Ph.D. from Columbia Teacher’s College. Sian is currently a mathematics educator based in New York City who helps young people discover and develop their own interest and ability in mathematics through playful activities that focus on mathematical reasoning and problem solving.

This course features…

  • An in-depth overview of the topic of logical reasoning and descriptors of what logical reasoning skills look like in middle schoolers.

  • Classic math problems such as “The Brownie Problem / Square Squares.”

This course is good for someone who…

  • Seeks a course that blends pedagogical insight with elegant content. This course could fit academics with less experience teaching young people or math coaches.

  • Is curious about more problems outside of the course. The course author wrote “Camp Logic,” a book that contains additional logic puzzles and activities that educators can build on.

Sample Problem

Archeologists found an ancient tablet with an unknown number system. The tablet showed the following equations:

ΔΔΙ+ ΔΙ = ΔΔΔΙΙ

Δ Ι + Δ ΙΙΙ = ΔΔΔ

ΔΔΔ ΙΙ + Δ Ι = ⨅ ΙΙΙ

Study the equations and use them to figure out how to count from 1 to 50 in this number system!