Released on this day in 1964, “A Hard Day’s Night” has confounded guitarists with its famous opening chord. Here’s why no one was ever able to play it correctly.

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Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

Can you chip in? As an independent nonprofit, the Internet Archive is fighting for universal access to quality information. We build and maintain all our own systems, but we don’t charge for access, ...

Apply for NCTM's Mathematics Education Trust grants, scholarships, and awards. Funding is available to help math teachers, prospective teachers, and other math educators improve the teaching and ...