Yutaka Nishiyama

A Study of Odd- and Even-Number Cultures

Japanese prefer odd numbers, whereas Westerners emphasize even numbers, an observation that is clear from the distribution of number-related words in Japanese and English dictionaries. In this article, the author explains why these two cultures differ by surveying the history of numbers, including yin-yang thought from ancient China, ancient Greek philosophy, and modern European mathematics. The author also mentions that oddness and evenness are only mathematical concepts, but understanding the cultures and histories of individual countries contributes to world peace.

Why Is a Flower Five-Petaled?

This paper examines why many flowers are five-petaled through the use of a five-petaled model that draws insights from the location of cell clusters at a shoot apex, rather than by way of the Fibonacci sequence or the golden ratio as in the past. The conclusion drawn is that flowers are most likely to be five-petaled, followed by six-petaled; four petals are unstable and almost no flower can be seven-petaled.

The World of Boomerangs

After touching on the three most common misconceptions regarding boomerangs, the author goes on to explain why a boomerang is crescent shaped.The author explains, using the principle of precession motion, why a boomerang turns leftward and why it falls sideways; and he performs a comprehensive analysis through the “right-hand rule,” using the example of a gyro top.The author also explains how to make and fly the boomerang he invented—one that can fly inside a room and come back correctly.

THE PROBABILITY OF CARDS MEETING AFTER A SHUFFLE

Even after giving a standard 52-card deck a good shuffle, there will likely be instances where two cards with the same number end up next to each other. This article concerns my investigations into the probability of such an occurrence. In the end I found that this is by no means an uncommon event, there being a 21.7% probability of finding two cards of a given number adjacent, and a 95.4% chance of finding at least one pair of adjacent samenumbered cards. I made these calculations using combinatorics for up to 20 cards, and a random number-based simulation for the cases of 24 to 52 cards. AMS Subject Classification: 60C05, 97K50, 00A08