## Introduction to the DaMath Board Game Part 1

DaMath is a math board game coined from the word dama, a Filipino checker game, and mathematics. It was invented by Jesus Huenda, a high school teacher from Sorsogon, Philippines. It became very popular in the 1980s and until now played in many schools in the Philippines.

DaMath can be used to practice the four fundamental operations and also the order of operations. It has numerous variations, but in the tutorial below, we will discuss the Integers DaMath. Note that explaining this game is quite complicated, so I have divided the tutorial into three posts.

The DaMath Board

The board is composed of 64 squares in alternating black and white just like the chessboard. The four basic mathematical operations are written on white squares as shown in Figure 1. Each square is identified by a (column, row) notation. The top-left square, for example, is in column 0 and row 7, so it is denoted by (0,7).  » Read more

## Guest Post: Combine Math and Excel on iPad with Image to Excel Converter

In today’s digital era, there are many helpful tools and apps that can give you a hand with handling different math assignments and tasks. The most common one and certainly the most used one is MS Excel. Even though the program in question is a pure classic, it facilitates and contributes a lot when it comes to various calculations and formulas. MS Excel acts like a super calculator and saves your time with both, simple and complex, mathematical operations. From summing, finding minimum and maximum functions, across calculating conditional statements, to computing statistics and more: let Excel do it for you instead of doing it manually.

Given that math calculations are mostly done in old-fashioned way on paper, it would be convenient to transfer them into Excel spreadsheet and in that manner to avoid rewriting all data by hand. Luckily, there is a useful app that can do all the tedious work.  » Read more

## Guest Post: Calculating Trignometric Values

Many students who start to learn Trigonometry often ask themselves how do we come to know that

$\sin 30^\circ = \frac{1}{2}$ or $\cos 45 ^\circ = \frac{\sqrt{2}}{2}$

or for that matter any other trigonometric value?

Most of us would say use a trigonometric table or use a scientific calculator and you get the value. That’s okay, but the question still remains unanswered. How does a calculator come to know that $\tan 15^\circ = 0.26794919...$ or how did the mathematicians create the entire trig tables when calculators were not invented? There should be some formula that tells us as to how the values are calculated. More importantly, can I, using a standard calculator, find the approximate value of let’s say $\sin 50.5^\circ$? Yes, there is a simple formula to find the value of sine of any acute angle. Though the formula does not give accurate results, it comes handy to know the value of $\sin \theta$  where $0^\circ \leq \theta \leq 90^\circ$.

$\sin x ^\circ = \frac{4x(180 - x)}{40500 - x(180 - x)}$.

This rational approximate formula was discovered by Bhaskara I of India in the seventh century. This simple formula enables us to calculate the sine of any given acute angle (any even obtuse angle) with a maximum absolute error of 0.00163.  » Read more

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