In order to keep the site online, we need to pay for hosting and other expenses. We're not looking to get rich, just to keep the site viable... and improve it as needed. For students, we're looking for a very modest $1 a month for the time you use the site. For teachers $5 a month seems fair. You can contribute easily and safely via Patreon below...
"...full of humor, insight and clarity. I wish every textbook was this good.”
"...much better than a book. It’s a superior way to learn this material.”
“...I can’t believe how many clips, graphics and animations are in here.”
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