Ask Dr. Math - Ask Dr. Math is a question and answer service for math students and their teachers brought to you by Drexel University's Math Forum

How Many? A Dictionary of Units of Measurement - If you ever needed to know information about hat sizes, wind chill scale, paper sheet sizes in the US vs. the rest of the world, and Apgar scores, this is the place for you. This collection of units of measure incorporates metrics, English units, and international systems.

Mathworld - Mathworld is a web-based mathematics encyclopedia for students, educators, researchers and math enthusiasts.

Almanacs
Art
Atlases
Audio Visual
Biographical Information
Business & Economics
Calculators & Conversion Tools
College Counseling
Copyright & Plagiarism
Dictionaries
Electronic Books (eBooks)
English as a Second Language
Encyclopedias
Entertainment
General Reference
Health
History and Social Studies
Interlibrary Loan
Libraries and Museums
Literary Resources
Mathematics
Modern & Classical Languages
News Sources
Performing Arts
Periodical Databases
Primary Documents
Science
Statistics
Travel
U.S. Government & Politics