diff --git a/multiply_service.py b/multiply_service.py
new file mode 100644
index 0000000..bea6a94
--- /dev/null
+++ b/multiply_service.py
@@ -0,0 +1,4 @@
+def multiply(string):
+    arguments = string.split("*")
+    result = int(arguments[0]) * int(arguments[1])
+    return result
diff --git a/src/calculator_application.py b/src/calculator_application.py
index c7f944a..c8e4576 100644
--- a/src/calculator_application.py
+++ b/src/calculator_application.py
@@ -1,6 +1,75 @@
-"""This module starts the application."""
-import calculator_view as calculator_view
+"""Module for the CalculationService class"""
+from tkinter import StringVar
+import divide_service as divide_service
+import multiply_service as multiply_service
 
 
-if __name__ == "__main__":
-    calculator_view.initialize_calculator()
+class CalculationService:
+    """""Class for keeping track of, and evaluating calculations"""""
+
+    # Constructor for the class
+    # Initializes a String expression and a StringVar equation
+    # StringVar is used because it is required for the tkinter text box
+    def __init__(self):
+        print("initialized")
+        self.expression = ""
+        self.equation = StringVar()
+
+    def press(self, num):
+        """Function to update the expression in the text entry box"""
+        # appends the new number to the existing expression
+        self.expression = self.expression + str(num)
+
+        # update the expression by using set method
+        self.equation.set(self.expression)
+
+    def equalpress(self):
+        """Function to evaluate the final expression"""
+
+        # using a try/except in order to catch errors
+        try:
+
+            # evaluate the expression/calculation
+            if "/" in self.expression:
+                total = str(divide_service.divide(self.expression))
+            if "*" in self.expression:
+                total = str(multiply_service.multiply(self.expression))
+            else:
+                total = str(eval(self.expression))
+               
+
+            if float(total) > 10:
+                total = total + " <:o)"
+
+            self.equation.set(total)
+
+            # reset the expression to the empty string
+            self.expression = ""
+
+        # show error on the screen after an exception is caught
+        except:
+            self.equation.set(" error ")
+            self.expression = ""
+
+
+
+    def clear(self):
+        """Function to clear the contents of text entry box"""
+        self.expression = ""
+        self.equation.set("")
+
+    def get_expression(self):
+        """get expression"""
+        return self.expression
+
+    def set_expression(self, newExpression):
+        """set expression"""
+        self.expression = newExpression
+
+    def get_equation(self):
+        """get equation"""
+        return self.equation
+
+    def set_equation(self, new_equation):
+        """set equation"""
+        self.equation.set(new_equation)