#1 RealCalc Scientific Calculator
It is an amazing scientific calculator for Android. I may say that this is the number one Android calculator. This fully-featured application includes all essential functions, can work in bin/hex/octal/dec modes, has a unit converter, can work with trigonometrical functions in degrees as well as in rads and grads.
Rating: 4.7
#2 WolframAlpha
It's a nice app where you can get answers on almost any questions about any academic discipline - from physics and math to the music and the web. You will get answers in table form with some graphics and without much of 'bla bla bla' like in Wikipedia. This apps comes directly from the parental web site Wolframaplha.com. I would recommend it to all students and teachers.
Rating: 4.6
#3 Formulas Lite
It's a good, easy to use and nice-looking helper to students. This app collects most of essential formulas of Chemistry, Physics and Math. It also includes a scientific calculator with graphs.
Rating: 4.5
#4 Thinking Space
To be honest, I love this app because I didn't find anything better for mind mapping for Convert Html Into Android App. I tell you more, it is the most useful app for Android tablets. It is 'an excellent app, intuitive and a great alternative to traditional note taking', the app user says.
Rating: 4.6
#5 Wikidroid
It's an another version of Wikipedia app that lets you download articles directly to your device. And this is good option if you need to collect some articles for your next article. This app also supports voice search, bookmarking and quick language swap.
Rating: 4.4
#6 Celeste SE
It's a beautiful app for everybody who love astronomy. It implements nice 3D graphics with some interesting facts about celestial bodies. It uses GPS coordinates and G-sensor to show you what you may see on the sky as if your Android tablet were a telescope.