I worked through a lot of this partial differential equations book during downtime while working in a gas station after my freshman year of college: https://ww

I worked through a lot of this partial differential equations book during downtime while working in a gas station after my freshman year of college: https://www.amazon.com/Differential-Equations-Scientists-Engineers-Mathematics/dp/048667620X https://www.amazon.com/Differential-Equations-Scientists-Eng... Might be a little advanced for most teenagers (I was 19 that summer), but I love the book and still refer to it from time to time. I did have experience with ordinary differential equations at the time, but I haven't found an ODE book that's quite the same.