[ddragon]

In Julia, the math part is mostly functional. Structs/Data are immutable by default (which cover most basic numeric types) and while arrays are mutable it's very common to write operations in the form of broadcasting (vectorized math) which will not mutate (and you have all higher order functions). In general most languages are this way to some extent (I don't know languages with mutable base numbers or math operators, outside of stuff like +=).

But mutability is also a great tool to have, for example for efficient dataframe handling and neural network weights.