Welcome to the fourth edition of the Mathematics and Multimedia Blog Carnival.
* Note: All images in this post are from Wikipedia.
The Number 4
- Four is the smallest composite number, its proper divisors being 1 and 2. Four is also a highly composite number. The next highly composite number is 6.
- Four is the second square number, the second centered triangular number.
- 4 is the smallest squared prime (p2) and the only even number in this form. It has an aliquot sum of 3 which is itself prime. The aliquot sequence of 4 has 4 members (4, 3, 1, 0) and is accordingly the first member of the 3-aliquot tree.
(2) Milo Gardner presents Ahmes Papyrus, New and Old Classifications posted at New and Old Ahmes Papyrus classifications,. The history of Western mathematics includes 200 rational number based problems recorded in Egyptian (2050 BCE to 1550BCE) unit fractions. The RMP is sometimes called Ahmes' Papyrus, named after its scribe. The hieratic text described 87 problems: 20 arithmetic, 10 algebraic, 10 geometric, 46 economic (weights and measures) and one mod 7 recreational problem known in the medieval era as "Going to St. Ives". Forms of unit fraction arithmetic remained in use until 1454 AD, the latest text was Fibonacci's Liber Abaci, Latin writing Europe's arithmetic book from 1202 AD to 1454 AD, and fully replaced by base 10 decimals by 1585 AD.
(3) Ed Pegg Jr presents Happy Vampire Day posted at Wolfram Blog. "October has a rather special day—10/05/2010 is a vampire date, since 10052010 = 5001 × 2010. The next two 8-digit vampire dates are 10/05/2064 and 10/19/2248. As a puzzle, try to figure out how to rearrange their digits into two 4-digit numbers, which have a product of the original number."
(4) zar presents Dimostrazione senza parole (demonstration without words) posted at Gli studenti di oggi. Zar's blog is written in Italian, but this particular post is "without words."
(5) Erlina Ronda presents GeoGebra and Mathematics: Investigating coordinates posted at Keeping Math Simple.
(6) John Golden presents Fraction Multiplication posted at Math Hombre -- A Geogebra visualization for multiplying fractions, along with a novice screencast and a discussion of embedding geogebra in a blog.
(7) William Emeny presents A sequences alternative to ‘how many matchsticks’ posted at Great Maths Teaching Ideas. "Make lessons on sequences much more interesting by adding context! Use sequences to analyse skyscrapers!"
(10) Rebecca Zook presents How To Multiply Binomials Using a Box! posted at Triangle Suitcase - Rebecca Zook's Blog About Learning. "Many people find this "box" method for multiplying binomials more intuitive than foiling. I created this series of short videos to share this idea with other math teachers and students."
(11) Guillermo Bautista presents Mathematics in Microsoft Office « Mathematics and Multimedia posted at Mathematics and Multimedia. This is an article on integrating mathematics to office suites.
(12) Last but not least, I submit my own review of The Mystery of the Prime Numbers. This is an amazing book, with great illustrations that looks like a children's book but will appeal to anyone who wants to dive deep into simple ideas.
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