diff --git a/src/main/java/com/garbagemule/MobArena/formula/BinaryOperation.java b/src/main/java/com/garbagemule/MobArena/formula/BinaryOperation.java
index 9a06a27..0a2c462 100644
--- a/src/main/java/com/garbagemule/MobArena/formula/BinaryOperation.java
+++ b/src/main/java/com/garbagemule/MobArena/formula/BinaryOperation.java
@@ -1,7 +1,8 @@
 package com.garbagemule.MobArena.formula;
 
-import java.util.function.BiFunction;
-
 @FunctionalInterface
-public interface BinaryOperation extends BiFunction<Double, Double, Double> {
+public interface BinaryOperation {
+
+    double apply(double left, double right);
+
 }
diff --git a/src/main/java/com/garbagemule/MobArena/formula/UnaryOperation.java b/src/main/java/com/garbagemule/MobArena/formula/UnaryOperation.java
index f27f200..4b91232 100644
--- a/src/main/java/com/garbagemule/MobArena/formula/UnaryOperation.java
+++ b/src/main/java/com/garbagemule/MobArena/formula/UnaryOperation.java
@@ -1,7 +1,8 @@
 package com.garbagemule.MobArena.formula;
 
-import java.util.function.Function;
-
 @FunctionalInterface
-public interface UnaryOperation extends Function<Double, Double> {
+public interface UnaryOperation {
+
+    double apply(double value);
+
 }