A maths student with lots of questions... I also answer to others when I can, which for the time being is rare but I hope will improve!
Mathematics
Q&A for people studying math at any level and professionals in related fields
Stack Overflow
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TeX - LaTeX
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Emacs
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Super User
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Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Ask Ubuntu
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MathOverflow
Q&A for professional mathematicians
French Language
Q&A for students, teachers, and linguists wanting to discuss the finer points of the French language
Ethereum
Q&A for users of Ethereum, the decentralized application platform and smart contract enabled blockchain