WolframAlpha - Review & Download
Warning: Users can download the app from the links of Google Play and AppStore offered in the following articles.

Wolfram Alpha gets its name from the founder, Stephen Wolfram, who created the online service to answer factual queries by using its massive algorithms and data. Unlike search engines, the answers it gives are only robust computational results instead of pages of web links or documents.

Average User Rating:
4.7, 1666 votes

Uninstall the app:

1. Go to Settings menu;

2. Choose Apps or Application manager;

3. Touch the app you want to remove;

4. Press Uninstall.

Features:

Apple Siri Assistant can help you fulfill some of the function.

This app gives you full access to Wolfram Alpha computational knowledge engine.

Wolfram Alpha covers by Many kinds of Domains.

WolframAlpha

For reference

Domains it covers:

Mathematics, Statistics & Data-Analysis, Physics, Chemistry, Materials, Engineering, Astronomy, Earth Science, Life Sciences, Computational Sciences, Units & Measures, Dates & Times, Weather, Places & Geography, People & History, Culture & Media, Music, Words & Linguistics, Sports & Games, Colors, Money & Finance, Socioeconomic Data, Health & Medicine, Food & Nutrition, Education, Organizations, Transportation, Technological World, and Web & Computer Systems.