Month: May 2011

All-time Top 10 Mathematics Posts

Top Posts
Here are the All-time Top 10 Mathematics posts  when it comes to number of hits. Try reading the documents to see why they are popular.
  1. How to use the summation symbol
  2. Tessellation: The Mathematics of Tiling
  3. An extensive explanation about the Epsilon-Delta definition of limits
  4. The Algebraic and Geometric Proofs of Pythagorean Theorem
  5. Why do we reverse/flip the inequality sign?
  6. Using Mathematics to Win the Lottery
  7. Arithmetic Sequences and Linear Functions
  8. Rational and Irrational Numbers
  9. Sum of the interior angles of a polygon
  10. Derivation of the Quadratic Formula
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Why Finger Multiplication Works

Elementary School Mathematics

In the Finger Multiplication post, we have learned how we can cleverly multiply numbers from 6 to 10 using  our fingers without memorizing the multiplication table. In this post, we will discuss the reason why this method works.  The proof can be written in a few lines, but since this article falls under the elementary school mathematics category, we will discuss it with more details.

Finger Multiplication of 8 x 7.

Let’s examine the first example in the previous article as shown above. In the example, we wanted to multiply 8 by 7, so we connected the ring and the middle fingers. In this discussion, we will call the connected fingers and all the fingers below them down fingers, while we call all the fingers above them up fingers. » Read more

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Experimental and Theoretical Probability Part 3

High School Mathematics, High School Probability

This is the third part of the Experimental and Theoretical Probability Series.

In the second part of this series, we have observed in three different experiments that if two dice are rolled, it seems that the probability of getting the sums are not equal. Not only that, we have seen several consistent patterns; for example, 2 and 12 got the least number of rolls; while, 6,7, and 8 got the most.

To investigate this observation, we examine how to get a sum of 2, 12, and 6 first when we roll two dice, and then investigate other sums later.  Recall that in the first part of this series, we experimented with two dice, one colored blue and the other red.  To distinguish which number belongs to which dice, we color the numbers blue and red to denote blue and red dice. » Read more

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