ID 256398466 © Tsupikovevgeniy | 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.:
school mathematics algebra education solution formula blackboard chalk pattern geometry equation white calculus green graph equalization teaching function split nobody seamless dirty wording math board physics stain complex science problem training instruction abrasion identity wipe phrase writing crack text line desk learning calculation flaw full eraser expression computing classroom shape