Mathematical notation around the world What are the differences in mathematical notation around the world? I know that in some other countries they write 1,2 meaning 1.2, but what else can be confusing in an academic environment (when people are doing math on a board or on paper). 
 A: 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...
A: Long division has different notations in different countries.Wikipedia has examples: Long division in Wikipedia 
A: 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.
A: 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 $AB^tA^{-1}$.
