Simple Blackboard is a free Android app developed by BitDeveloper that allows you to draw, jot, and illustrate on a simple blackboard or whiteboard. The app offers a range of features, including various brush sizes and color options, the ability to draw different shapes, add text, load photos, and record videos. Additionally, you can save your drawings to your device gallery, add or remove pages, and set your favorite paint colors and color opacity. The app ensures that the device screen never goes off while you're using it, making it convenient for extended use.

That said, the app is ad-supported, and some features, such as adding text, drawing shapes and grid, and setting favorite paint colors, are only available through a premium purchase. Overall, Simple Blackboard is a useful app for anyone looking to draw, jot, or calculate on their device without the need for pen and paper.