ID 114145934 © Trifff | 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.:
abstract algebra background black blackboard board calculate calculus chalk chalkboard class classroom college complex education equation exam figure formula geometry grunge learn lesson line math mathematics minus number old physics problem proof school science scratch scribble sign slate solution study symbol teach teacher theory vintage white write