Dropmark is a cool app that you can put all your stuff in one simple, visual place. It is completely private and 100% ad free. You can easily organize links, photos, videos, documents, audio, and text notes into visual collections. You can control the privacy and keep your content to yourself, invite colleagues, or you can go public. Each collection has its own sharable short link and accessible on the web.
Math is Fun
Math is Fun offers mathematics in an enjoyable and easy-to-learn manner, because they believe that mathematics is fun.