The meaning of $\mathbb R^n$ in $f:\mathbb R^n \rightarrow \mathbb R$

Question

I'm just making my way in Math and I apologise for the ease of this question. I don't understand what $\mathbb R^n$ in $f(x):\mathbb R^n \rightarrow \mathbb R$ actually means.

Answer 1

^{Compiled from comments by user84413}

This just means that the domain of the function is $\mathbb R^n$, so it is defined for $n$-tuples of numbers.

Its inputs are an ordered set of $n$ numbers, and its outputs are just $1$ number. As a simple example, we could let $f:\mathbb R^{2}\rightarrow \mathbb R$ be defined by $f(x,y)=x^2+5y$.

In general, an element of $\mathbb R^n$ is denoted by $(x_1,x_2,\cdots,x_n)$ where the $x_i$ are real numbers.