Thursday, March 24, 2011

Vocabulary List

In high school English class, I was sometimes given lists of 20 vocabulary words weekly to store in short-term memory to recite for the weekly test. Many of the words were hard and I never get to use them in real life after the test. It was painful experience to learn new words.

Flash card is a good way to learn words. Write words on one side, write definitions on another side. Flip through them and memorize them.

Now this learning process can be even better with this app.

You can type your definitions or use google translate to translate vocabulary to your native language, and hear it pronounced to you with the Text-To-Speech library from Android.

You can use virtually flip flash cards or quiz yourself. I wish you score high in your next vocabulary test.

Get Yours On Android Market

Graph 2D

Most phones come with a handy 4 function calculator. Android's calculator even give you some scientific functions. Nice. How about graphing? Most of your algebra and calculus class want you to find out properties of functions... where are the zeros? what are the y intercepts, etc. And graphs give you a visual view.

The idea of graphing is real simple. Give a list of x, plug that in the function to get a (x,y) to plot. But the catch is... how do you evaluate a function given a String of it? and how do you put a graph, let's say a box of (-5,-5) to (5,5) to a computer screen of (0,0) to (width,height)?

Evaluating a function is no trivial task for a non-interpreted language like C or Java. If you are interested you can see here. About plotting, we need to scale and translate the points.

Now with the touch screen, I can do something that a typical graphing calculator cannot do... and that is swipe on the screen and see the graph move.

Get Yours on Android Market

Arithmetic Demo

Kids grow up doing arithmetic drills. Dozens of them on a worksheet, for days, weeks, months. I did not need THAT many to master my arithmetic.

Kids (and adults), do you know why we do paper-pen methods of arithmetic the way we do them?

Sure we can do 1 digit calculations in our head. But adding a 2 digit by 2 digit gets too hard. We need to break down into pieces and add up the results... and our base-10 system makes it easy to do so.

I want to automate the mundane calculation process. Sure, there is the calculator, a very important invention.

But calculators do the job too fast. The steps are missing.

Here we are: the Arithmetic Demo. Enter your own numbers and see the calculation in process.
Just keep hitting the Next button.

This app is merged into Math Experiments.

Wednesday, March 23, 2011


Welcome to my Android blog! In this blog I will tell you about my Android apps as well as sharing about Android programming tips.