How to read $\frac{d^2y}{dx^2}$

Three ways of reading $\dfrac {d^2 y}{dx^2}$...

1. "dee squared y over dee x squared" (your way)
2. "dee two y over dee x two" (informal)
3. The second derivative of $y$ with respect to $x$ (formal)

Formally, you should say : second order derivative of y w.r.t. x

I'm pretty sure you read it either

• dee two y by dee x squared

or

• dee two y over dee x squared

(either is fine)