Check our math operations

[skx]

I've been reading this:

• https://gigamonkeys.com/book/numbers-characters-and-strings.html

I see:

For example, (+ 1 2 3) is equivalent to (+ (+ 1 2) 3). With only one argument, + and * return the value; - returns its negation and / its reciprocal.9

That implies :

• (/ 4) -> 1/4
• (* 34) -> 34
• (+ 21) -> 21

Right now the first won't work, though it seems by happy accident that the second two do work:

$ yal -e "(print (* 4))"
4
$ yal -e "(print (+ 32.4))"
32.400000