primitive factorial does not work on a value of type real

[lefessan]

lycee()
exp(10)/factorielle(10)

String "box-2", line 1, characters 8-23:
String "factorielle.sci", line 16, characters 4-16:
Error: primitive factorial does not work on a value of type real
Hint: you can try redefining %s_factorial
⇊Insert a new box after this one.