diff --git a/jtwig-core/src/main/java/org/jtwig/util/MathOperations.java b/jtwig-core/src/main/java/org/jtwig/util/MathOperations.java
index 66791ff5..e32f7626 100644
--- a/jtwig-core/src/main/java/org/jtwig/util/MathOperations.java
+++ b/jtwig-core/src/main/java/org/jtwig/util/MathOperations.java
@@ -56,10 +56,13 @@ public static int toInt (Object obj) {
     }
 
     public static boolean areDouble(Object... list) {
+    	if (list == null || list.length == 0) 
+    		return false;
+    	
         for (Object obj : list)
-            if (obj instanceof Double)
-                return true;
+            if (!(obj instanceof Double))
+                return false;
 
-        return false;
+        return true;
     }
 }
diff --git a/jtwig-core/src/test/java/org/jtwig/unit/util/MathOperationsTest.java b/jtwig-core/src/test/java/org/jtwig/unit/util/MathOperationsTest.java
index e2c04280..6232a518 100644
--- a/jtwig-core/src/test/java/org/jtwig/unit/util/MathOperationsTest.java
+++ b/jtwig-core/src/test/java/org/jtwig/unit/util/MathOperationsTest.java
@@ -14,10 +14,15 @@
 
 package org.jtwig.unit.util;
 
-import org.junit.Test;
-
-import static org.jtwig.util.MathOperations.*;
+import static org.jtwig.util.MathOperations.areDouble;
+import static org.jtwig.util.MathOperations.intDiv;
+import static org.jtwig.util.MathOperations.mod;
+import static org.jtwig.util.MathOperations.sum;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
 
 public class MathOperationsTest {
     @Test
@@ -32,4 +37,21 @@ public void modTest() throws Exception {
     public void intDivDoubleTest() throws Exception {
         assertEquals(1, intDiv(2.0, 2.0));
     }
+    @Test
+    public void areDoubleTest() {
+    	assertTrue(areDouble(1.0,2.0));
+    }
+    @Test
+    public void areDoubleWithStringAndDoubleTest() {
+    	assertFalse(areDouble("1.0",2.0));
+    }
+    @Test
+    public void areDoubleEmptyParameterListTest() {
+    	assertFalse(areDouble());
+    }
+    @Test
+    public void areDoubleNullParameterListTest() {
+    	Object[] parameterList = null;
+    	assertFalse(areDouble(parameterList));
+    }
 }