Mathematical notation around the world

As seen here, in some countries a diagonal bar is used before the function to denote evaluation (not sure if it's in general or just in the integration case). That is: $$ \int_{0}^1 x\,dx=\mathop{\Big/}\nolimits_{\hspace{-2mm}0}^{\hspace{1mm}1}\frac{x^2}{2} $$ is used instead of what many users here would find to be the convention: $$ \int_{0}^1 x\,dx=\frac{x^2}{2}\mathop{\Big|}\nolimits_{0}^{1}. $$

Then you also, of course, have different ways of denoting derivatives - Leibniz', Euler's, Newton's, etc...

Long division has different notations in different countries.Wikipedia has examples: Long division in Wikipedia

I've noticed that Anglo-Saxons use $\displaystyle{n\choose k}$ instead of $C_n^k$ for combinations or binomial coefficients. Also, repeated decimals are placed between (...) instead of being overlined, which helps avoid errors.

Function composition, in the context of group theory (a permutation is a bijection from a set onto itself), can be written

$$(fg)(x)=f(g(x))$$

Or

$$(fg)(x)=g(f(x))$$

The latter seems to be (or have been) used by some anglo-saxon mathematicians, and appears in books by Burnside, and Passman.

Also, matrix transpose is denoted $^tA$ in France, while it seems to be $A^T$ mostly everywhere else. This can be confusing when you write a product: $AB^TA^{-1}$ is of course not the same as $AB^tA^{-1}$.