diff --git a/lib/operators.c b/lib/operators.c
index b415a04..8c3bcba 100644
--- a/lib/operators.c
+++ b/lib/operators.c
@@ -8,6 +8,7 @@
 #include  <stdlib.h>
 #include  <unistd.h>
 #include  <string.h>
+#include  <math.h>
 
 #include  "../floatimg.h"