# Math From Scratch 16: Divisibility Rules (for base 10)

The results for testing numbers for divisibility in base 10 are laid out here. It appears we’ll be reaching the rational numbers at some point in the spring of 2012.

# Math From Scratch 15: The Fundamental Theorem of Arithmetic

The fifteenth lesson of the Math From Scratch series, dealing with the Fundamental Theorem of Arithmetic, is available here.

# Math From Scratch schedule changes

As some of you know, I have bilateral elbow tendinitis. As a result, I need to reduce the amount of time spent sitting in front of a keyboard. Unfortunately, this has forced me to slow down on the “Math From Scratch” series. From this point on, new lessons will appear on the first of each month, with lesson 15 due November 1. July and August, the “Summer school” month, will be skipped. Thus, there will now be ten lessons per year. Check the Bureau 42 calendar for updates.

# Math From Scratch 14: Defining Division With Remainder

The next chapter in the Math From Scratch series is available here. We can now define a division algorithm involving remainder.

# Math From Scratch 13: Metric Spaces Other Than Canada

We can finally define distances, which allows us to establish the number line. Those tools are presented in lesson 13: Metric Spaces Other Than Canada.

# Math From Scratch 12: Other Bases

With the bases representation theorem established, we can examine the bases that are common to computer science, and how they have plagued some of the more adept Nintendo players of by generation. Lesson 12: Other Bases.

# Math From Scratch 11: Introducing Base 10

In our eleventh lesson, we can formally justify the number representation we inherited from Arab mathematicians so many centuries ago. I hope you enjoy All Your Bases Are Belong To Us.

# Math From Scratch 0010: Introduction to Rings

Our tenth lesson introduces ring theory, which allows us to define several familiar concepts: One Algebra To Rule Them All. Remember, past lessons can all be found by clicking on the “math from scratch” tag below.

# Math From Scratch 0009: Cosets and Lagrange’s Theorem

Part nine of a number that I hope will be finite: Cosets and Cardinality. Remember, past lessons can all be found by clicking on the “math from scratch” tag below. Also, try as I might, I couldn’t find a natural ZZ Top reference to work into this lesson dealing with Lagrange’s Theorem. Suggestions are welcome in the space below.

# Math From Scratch 0008: Mappings and Functions

Part eight of a number that just keeps getting bigger: Mappings and Functions. Remember, past lessons can all be found by clicking on the “math from scratch” tag below.