"Mathematics"
 When mathematical structures are good models of real phenomena, then mathematical reasoning can provide insight or predictions about nature. ​
​https://en.wikipedia.org/wiki/Mathematics

Eulers Number

MATH IS FUN
Picture
To Website

Lagrangian Mechanics: How powerful is it?

THE SCIENCE ASYLUM
Picture
To Website
  https://www.youtube.com/watch?v=MIBfKJHMWHU
Some helpful Wikipedia links: