Define new operators:
Let's define "+" not as add, but as multiply:

>'+' <- function(x,y) x * y
>3 + 5

[1] 15

Let's delete the self defined operator "+":

>rm('+')
>3 + 5

[1] 8

> 3 * 4 - 2
[1] 10
> 1:4 + 1
[1] 2 3 4 5
> (1:4) + 1
[1] 2 3 4 5
> 1:(4 + 1)
[1] 1 2 3 4 5
>  1:4 * 2
[1] 2 4 6 8
>  1:4 ^ 2
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16
> -4:-2
[1] -4 -3 -2