diff --git a/src/main/java/parser/Function.java b/src/main/java/parser/Function.java
index 2ac2506..3ad3beb 100644
--- a/src/main/java/parser/Function.java
+++ b/src/main/java/parser/Function.java
@@ -8,6 +8,7 @@
 import parser.methods.Method;
 
 import java.io.StringReader;
+import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 import java.util.InputMismatchException;
 import java.util.List;
@@ -223,7 +224,7 @@ public double calc(double... x) {
         return Double.NaN;
     }
 
-    public static boolean assignObject(String input, Class mathExpClass) {
+    public static <T extends MathExpression> boolean assignObject(String input, Class<T> clazz) {
 
         /**
          * Check if it is a function assignment operation...e.g:
@@ -273,7 +274,15 @@ public static boolean assignObject(String input, Class mathExpClass) {
 
                 success = true;
             } else {
-                MathExpression expr = mathExpClass == BigMathExpression.class ? new BigMathExpression(rhs) : new MathExpression(rhs);
+                MathExpression expr;
+                try {
+                    expr = clazz.getConstructor(String.class).newInstance(rhs);
+                } catch (InstantiationException |
+                         IllegalAccessException |
+                         InvocationTargetException |
+                         NoSuchMethodException e) {
+                    throw new RuntimeException(e); // unreachable
+                }
                 String val = expr.solve();
                 String referenceName = expr.getReturnObjectName();
                 //System.out.println("rhs: "+rhs+", mathExpClass: "+mathExpClass+", expr.class: "+expr.getClass()+", val: "+val+", type: "+expr.getReturnType());
diff --git a/src/main/java/util/MathExpressionManager.java b/src/main/java/util/MathExpressionManager.java
index 8032711..e9544b3 100644
--- a/src/main/java/util/MathExpressionManager.java
+++ b/src/main/java/util/MathExpressionManager.java
@@ -247,10 +247,10 @@ public MathExpression createFunction( String expr ){
      * it has to interpret and then evaluate it.
      * It then stores the expression.
      * @param expr The expression to evaluate.
-     * @param mathExpClazz The java.util.Class that the parent MathExpression belongs to.. may be MathExpression.class, BigMathExpression.class etc.
+     * @param clazz The java.util.Class that the parent MathExpression belongs to.. may be MathExpression.class, BigMathExpression.class etc.
      * @return the result.
      */
-    public String solve( String expr , Class mathExpClazz) throws NullPointerException{
+    public <T extends MathExpression> String solve(String expr, Class<T> clazz) throws NullPointerException{
         try {
             CustomScanner cs = new CustomScanner( STRING.purifier(expr), false, VariableManager.endOfLine);
 
@@ -260,7 +260,7 @@ public String solve( String expr , Class mathExpClazz) throws NullPointerExcepti
 
             for(String code : scanned) {
                 if(code.contains("=")){
-                    boolean success =  Function.assignObject(code+";", mathExpClazz);
+                    boolean success =  Function.assignObject(code+";", clazz);
                     if(!success) {
                         throw new Exception("Bad Variable or Function assignment!");
                     }