Dodeca and Icosa discuss how to multiply and divide by 100 and 1 000. Please click on the comic strip to enlarge if necessary.

Octa and Hexa discuss how to multiply and divide by 10. Please click on the comic strip to enlarge if necessary.

These seem to be impossible at first to solve. But with a bit of logic, ahaha! up comes the solution. Please click on the file name to see the pdf file.

Some Fermi Problems (or any number)

Using a technique that I learned 35 years ago, I can still remember phone numbers from that time. Please click on the file name to see the pdf file.

How to Memorize Phone Numbers (or any number)

Here is a neat little trick that does take some memorizing in order to use it. I explain how the tables are invented as well.

How to Find the Day of the Week for any Date

When coincidences appear to happen, what is the probability that they are coincidences, or should we expect to see them happen quite often. Please click on the file name to see the pdf file.

Using Probability to Check Coincidences

Here is a short post on this famous 20th Century mathematician. Please click on the file name to see the pdf file.

John Von Neumann, the “Father” of Computers

Using the first formula of working with radicals, we learn two methods of simplifying radicals. Please click on the file name below to see the pdf file.
Simplifying Radicals

Simplifying Radicals

Observing patterns is so much a part of the mathematical process, that it should not be considered unlikely that a new branch of mathematics could come from doing just that. Read the pdf file below by clicking on the file name.

Benoit Mandelbrot, the “Father” of Fractals

This post finishes off the section on sequences and series with a look at the sums of geometric series. Please click on the file name to see the pdf file.

Geometric Series