Month: January 2013

Video: Japanese Multiplication Algorithm

High School Mathematics

This video shows how the Japanese multiplication algorithm (sometimes called Vedic multiplication) which uses lines and their intersections to multiply two positive integers. It also shows the algorithm can be used to multiply numbers in other bases.  Shaun Klassen of Math Concepts Explained has also written a post about it.

Some things to think about:

  1. Why does the method work?
  2. What basic geometric concept does this algorithm relate to?
  3. What if the numbers you multiply contains zeroes?
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The Prime Composite Dance

Resources and Freebies, Teaching Tools, Web 2.0 Technology

In this blog, I have written quite a number of articles about prime numbers. In one of my posts, I have emphasized that geometrically, the dots that represent a prime number can only be arranged in a 1 x p rectangular arrangement where p is prime.  Composite numbers on the other hand, can be arranged geometrically into more than 1 rectangular arrangements.

prime-composite-dance

Stephen Von Worley has given a more beautiful definition of primes and composites in his  Factor Dance Animation .  The brilliant animation is a rearrangement of dots (circles) that represent numbers into different groups every second. Its aim is to show the “compositeness” and “primeness”  of numbers from 1 up to 10,000. Worley’s program used the algorithm Brent Yorgey, the writer of The Mathematics Less Traveled.

You can read more about the animation at Wolrey’s post titled Dance, Factors, Dance. You may also want to watch the beautiful animation.

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Book Review: Calc for the Clueless I

Book Review, High School Calculus, High School Mathematics

Almost a year ago, I bought Mr. Bob Miller’s Calc for the Clueless series for a younger cousin (I, II, and III), and she returned the book to me after finishing her Calculus class.   Last week, I started reading Calc for the Clueless: Calc I and found it to be very student friendly.  Most examples are easy to follow, and the book contains practical tips in solving problems. The book has also a chapter  solely dedicated to worked out maxima and minima problems.

What stands out in Calc for the Clueless: Calc I is its chapter on Curve Sketching. The author has detailed the methods of basic curve sketching and explained clearly the roles of intercepts, asymptotes, and the test for round minimums and maximums. There are a lot of step by step tutorials on sketching polynomial and rational functions.

Overall, I think  Calc for the Clueless: Calc I is a good companion book for students who want to learn self study Calculus especially those who are non mathematics majors.

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