Year: 2014

Misconception About Venn Diagrams

High School Mathematics

Last year, I had a good discussion with some teachers about Venn diagrams. Several teachers commented that I should change the diagram below because it might give an impression that the number of rational numbers is the same as the number of irrational numbers. Sadly, I was not sure if I was able to explain my point. Anyway, below is an extended explanation to those comments.

Venn diagrams usually represent the logical relationships among sets. They do not concern with their cardinality (the number of elements). For example, if sets A and B have common elements, then their relationship can be represented by any of the three Venn diagrams below. In creating Venn diagrams, you do not represent if there is only one common element, or there are many: you are representing if there are common elements or  there are none. » Read more

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Math Fun: How to Count in Japanese

Fun and Jokes, High School Mathematics

I am currently in Japan, so I thought that maybe I should share to you a little bit of Japanese mathematics. Counting is Japanese is easy. Try if you can see the pattern below.

How to Count in Japanese

1 to 10: ichi (1), ni (2), san (3), yon/shi (4), go (5), roku (6), nana/shichi (7), hachi (8), kyuu/kuu (9), juu/too (10).

11 to 20: juu ichi (11), juu ni (12), juu san (13), juu yon (14), juu go (15), juu roku (16), juu nana (17), juu hachi (18), juu kyuu (19), ni juu.

21 to 30: ni juu ichi (21), ni juu ni (22), ni juu san (23), and so on.

30 – 90 by tens: san juu (30), yon juu (40), go juu (50), roku juu (60), nana juu (70), hachi juu (80), kyuu juu (90)

100 – 900 by hundreds: hyaku (100), ni hyaku (200), sanbyaku (300), yon hyaku (400), go hyaku (500), roppyaku (600), nana hyaku (700), happyaku (800), kuu hyaku (900)

1000: sen

Examples:

28: ni juu hachi

67: roku nana or roku shichi

135: hyaku san juu go

1765: sen nana roku juu go

I hope you enjoyed learning how to count in Japanese. 🙂

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Math and Multimedia New Year Update

High School Mathematics

Happy New Year to all. This past week, during the winter break, I was able to update some of the pages of Mathematics and Multimedia. Before, I lost many links of the free ebooks but now, they are all updated. I have also added some new ebooks, so you may want to check out the following pages.

Of course, you might also want to look at the Free Probability and Statistics Ebooks and the new Free Plane, Solid, and Analytic Geometry Ebooks.

In addition, I have also updated the Age Problem Series (Part 1, Part 2) which is part of the Math Word Problem Solving Series.

If you have also recall Mathematical Palette, the blog that I abandoned before, I am turning it to a photo blog (check out my two new photos). It will contain photos that are related to mathematics. You may use the photos provided you link back to the original post.

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