2014 - Page 5 of 27 - Math and Multimedia

Solving Problems by Eliminating Impossible Cases

November 1, 2014 GB High School Mathematics, Problem Solving and Proofs

One of the strategies in solving problems is to divide them into cases and see if you can eliminate some impossible cases. In this post, I will discuss a popular classic problem which I found the solution to be interesting.

Problem

If A, B, C, and D are distinct non-zero digits, find their values if ABCD × 4 = DBCA.

If you have not encountered this problem before, you might want to solve it first before reading the solution below.

Finding the Value of A

Solution

One of the most obvious hints of the problem is that the value of A is only limited to 1 and 2. Why? Because if A is greater than 2, 4 × A will become a 2-digit number. This will make the product of ABCD × 4 a 5-digit number which does not satisfy the problem. » Read more

Youngest Math Teacher? 4-Year Old Explains Area of a Pentagon

October 18, 2014 GB Miscellaneous

Who is the youngest math teacher you know? Well, there’s a 99% probability that the teacher in the video below is younger. His name is Miguel Secillano III and he is 4. The way he explains solutions to math problems is way too amazing for his age.

Watch the video below as he explains how to get the area of a pentagon and see for yourself.

Miguel, according to his father, started counting from 1-100 when he was 2 and became interested in mathematics when he was turning four. He will turn 5 this December.

You can watch more of Miguel’s video in his Youtube channel.

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How to Calculate Using Japanese Abacus Part 1

October 17, 2014 GB High School Mathematics, Miscellaneous

In Japanese language, the abacus is called soroban. In this tutorial, we are going to learn how to use the soroban. In Japan, students start learning how to use abacus formally in the third grade.

Believe it or not, in these modern time, some tellers in Japan still use abacus. And when they calculate, they are almost as fast as when using a calculator. Or maybe even faster.

Shown above is a figure representing a Japanese abacus. » Read more

Leave a comment how to use a japanese abacus, japanese abacus, japanese abacus soroban, soroban

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