/ function computes division or reciprocal. When called with one argument it computes reciprocal. When called with two or more arguments it does compute division of the first by the all remaining number. It does type conversions for numbers. It works for all number types including integer, rational, floating point and complex. Note that division by zero invokes DIVISION-BY-ZERO condition.

(/ 10) => 1/10
(/ 10.0) => 0.1

(/ 10 2) => 5
(/ 2 10) => 1/5
(/ 100 2 5 2) => 5
(/ 100 (* 2 5 2)) => 5

(/ 1234567890123456789 9876543210987654321) => 13717421/109739369
(/ 1.3 -5) => -0.26
(/ 1.3d0 -5) => -0.26d0
(/ #c(2 4) 3) => #C(2/3 4/3)
(/ 3/4 7/9) => 27/28