ID 136822795 © Elnur | Megapixl.com
Sharing is not just caring, it's also about giving credit - add this image to your page and give credit to the talented photographer who captured it.:
academic algebra blackboard board book books chalk chalkboard class classroom college discussing education equation exam explaining formula green knowledge laboratory learn learning lecture lecturer lesson man math mathematic mathematical mathematician mathematics noise physicist physics professor school science shh silence silencing sound student study teacher teaching test textbook textbooks tutor university