public void EvaluateSimpleMultiplicationSymbolicAndValueResult()
 {
     var addition = new Multiplication(new Number("a"), new Number("4.6"));
     Assert.AreEqual("a*4.6", ((Number)addition.Evaluate()).ToString());
 }
 public void EvaluateSimpleMultiplicationValueResult()
 {
     var addition = new Multiplication(new Number("2.6"), new Number("4.8"));
     Assert.AreEqual("12.48", ((Number)addition.Evaluate()).ToString());
 }