diff --git a/kalk/src/kalk_num/regular.rs b/kalk/src/kalk_num/regular.rs
index 0dd5332..cf5b338 100644
--- a/kalk/src/kalk_num/regular.rs
+++ b/kalk/src/kalk_num/regular.rs
@@ -107,7 +107,7 @@ impl KalkNum {
     }
 
     pub(crate) fn pow_without_unit(self, rhs: KalkNum) -> KalkNum {
-        if self.has_imaginary() || rhs.has_imaginary() {
+        if self.has_imaginary() || rhs.has_imaginary() || (self.value < 0f64 && rhs.value < 1f64) {
             let a = self.value.clone();
             let b = self.imaginary_value.clone();
             let c = rhs.value;
diff --git a/kalk/src/kalk_num/with_rug.rs b/kalk/src/kalk_num/with_rug.rs
index c34b02c..b230395 100644
--- a/kalk/src/kalk_num/with_rug.rs
+++ b/kalk/src/kalk_num/with_rug.rs
@@ -65,7 +65,7 @@ impl KalkNum {
     }
 
     pub(crate) fn pow_without_unit(self, rhs: KalkNum) -> KalkNum {
-        if self.has_imaginary() || rhs.has_imaginary() {
+        if self.has_imaginary() || rhs.has_imaginary() || (self.value < 0f64 && rhs.value < 1f64) {
             let a = self.value.clone();
             let b = self.imaginary_value.clone();
             let c = rhs.value;