diff --git a/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/NumberOperationContributor.java b/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/NumberOperationContributor.java
index ec6db3cc8..2026e6127 100644
--- a/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/NumberOperationContributor.java
+++ b/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/NumberOperationContributor.java
@@ -9,7 +9,12 @@
  ******************************************************************************/
 package org.eclipse.epsilon.eol.execute.operations.contributors;
 
+import java.util.Arrays;
+import java.util.List;
 import java.util.stream.LongStream;
+
+import org.eclipse.epsilon.eol.types.EolPrimitiveType;
+import org.eclipse.epsilon.eol.types.EolType;
 import org.eclipse.epsilon.eol.types.NumberUtil;
 
 public class NumberOperationContributor extends OperationContributor {
@@ -19,6 +24,11 @@ public boolean contributesTo(Object target) {
 		return target instanceof Number;
 	}
 	
+	@Override
+	public List<EolType> contributesToType() {
+		return Arrays.asList(EolPrimitiveType.Real, EolPrimitiveType.Integer);
+	}
+	
 	@Override
 	protected Number getTarget() {
 		return (Number) super.getTarget();
diff --git a/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/OperationContributor.java b/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/OperationContributor.java
index 7a9c94389..0866f235a 100644
--- a/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/OperationContributor.java
+++ b/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/OperationContributor.java
@@ -11,12 +11,15 @@
 package org.eclipse.epsilon.eol.execute.operations.contributors;
 
 import java.lang.reflect.Method;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
 import org.eclipse.epsilon.common.parse.AST;
 import org.eclipse.epsilon.eol.dom.Expression;
 import org.eclipse.epsilon.eol.execute.context.IEolContext;
 import org.eclipse.epsilon.eol.execute.introspection.java.ObjectMethod;
+import org.eclipse.epsilon.eol.types.EolAnyType;
+import org.eclipse.epsilon.eol.types.EolType;
 import org.eclipse.epsilon.eol.util.ReflectionUtil;
 
 /**
@@ -33,6 +36,10 @@ public abstract class OperationContributor implements AutoCloseable {
 	
 	public abstract boolean contributesTo(Object target);
 	
+	public List<EolType> contributesToType() {
+		return Arrays.asList(EolAnyType.Instance);
+	}
+	
 	public ObjectMethod findContributedMethodForUnevaluatedParameters(Object target, String name, List<Expression> parameterExpressions, IEolContext context) {
 		// Note that the last parameter is false: we only want to retrieve methods that take an AST as an argument
 		// and not methods that take a supertype of AST (such as Object)
diff --git a/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/StringOperationContributor.java b/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/StringOperationContributor.java
index 514a74b77..5eb4fcfaa 100644
--- a/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/StringOperationContributor.java
+++ b/plugins/org.eclipse.epsilon.eol.engine/src/org/eclipse/epsilon/eol/execute/operations/contributors/StringOperationContributor.java
@@ -11,6 +11,7 @@
 
 import java.io.FileOutputStream;
 import java.io.StringWriter;
+import java.util.Arrays;
 import java.util.List;
 
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -35,8 +36,8 @@ public boolean contributesTo(Object target) {
 	}
 	
 	@Override
-	public EolType contributesToType() {
-		return EolPrimitiveType.String;
+	public List<EolType> contributesToType() {
+		return Arrays.asList(EolPrimitiveType.String);
 	}
 	
 	public Object toEnum() throws Exception {
diff --git a/plugins/org.eclipse.epsilon.eol.staticanalyser/src/org/eclipse/epsilon/eol/staticanalyser/EolStaticAnalyser.java b/plugins/org.eclipse.epsilon.eol.staticanalyser/src/org/eclipse/epsilon/eol/staticanalyser/EolStaticAnalyser.java
index 0d1e96be9..5f451a20d 100644
--- a/plugins/org.eclipse.epsilon.eol.staticanalyser/src/org/eclipse/epsilon/eol/staticanalyser/EolStaticAnalyser.java
+++ b/plugins/org.eclipse.epsilon.eol.staticanalyser/src/org/eclipse/epsilon/eol/staticanalyser/EolStaticAnalyser.java
@@ -1199,7 +1199,14 @@ public void preValidate(IEolModule imodule) {
 		//Parse builtin operations
 		List<OperationContributor> operationContributors = context.operationContributorRegistry.stream().collect(Collectors.toList());
 		for(OperationContributor oc: operationContributors) {
-			EolType contextType = toStaticAnalyserType(oc.contributesToType());
+			List<EolType> contextTypes = oc.contributesToType().stream().map(t -> toStaticAnalyserType(t)).collect(Collectors.toList());
+			EolType contextType;
+			if (contextTypes.size() == 1) {
+				contextType = contextTypes.get(0);
+			}
+			else {
+				contextType = new EolUnionType(contextTypes);
+			}
 			
 			for(Method m: oc.getClass().getDeclaredMethods()) {
 				List<EolType> operationParameterTypes = new ArrayList<EolType>();
@@ -1251,6 +1258,8 @@ public EolType javaClassToEolType(Class<?> javaClass) {
 		} else if (javaClass == Double.class || javaClass == double.class || javaClass == Float.class
 				|| javaClass == float.class) {
 			return EolPrimitiveType.Real;
+		} else if (javaClass == Number.class) {
+			return new EolUnionType(EolPrimitiveType.Real, EolPrimitiveType.Integer);
 		} else if (javaClass == boolean.class || javaClass == Boolean.class) {
 			return EolPrimitiveType.Boolean;
 		} else if (javaClass == java.util.Collection.class) {
@@ -1508,6 +1517,15 @@ public boolean canBeCompatible(EolType targetType, EolType valueType) {
 			return false;
 		}
 		
+		if (targetType instanceof EolUnionType) {
+			for (EolType t : ((EolUnionType)targetType).containedTypes) {
+				if (canBeCompatible(t, valueType)) {
+					return true;
+				}
+			}
+			return false;
+		}
+		
 		while (true) {
 
 			if (!(targetType.equals(valueType)) && !(valueType instanceof EolAnyType)) {