very minor edits

Calculator.java

             } else {
                 switch (toDo) {
                     //System.out.println("toDO is: " + toDo);
+                    
                     case "add":
                     case "subtract":
                     case "multiply":
                     case "tangent" :
                     case "inverse tangent" :
                     case "inverse" :
-                    case "M+" :
+                    
                     System.out.println(toDo + " -- Enter first number:");
                     num1 = input1.nextDouble();
                     //System.out.println("num1 is: " + num1);
                 }
                 switch (toDo){
+                    // case "previous":
+                    // num1 = lastAns;
+                    // System.out.println(toDo + " -- Enter second number:");
+                    // num2 = input1.nextDouble();
+                    //break;
                     case "add":
                     case "subtract":
                     case "multiply":
                 }
 
                 switch (toDo) {        
+                    
+                    
                     case "add":
                     result = calc.add(num1, num2);
                     lastAns = result;
                     break;
 
                     case "M+" :
-                    System.out.println("Enter number:");
-                    num1 = input1.nextDouble();
-                    result = Memory.memUpdate(num1);
+                    result = Memory.memUpdate(lastAns);
                     Memory.printAns(String.valueOf(result));
                     break;
 

MathMethods.java

 
     public static String fortuneCookie() {
         Random rand = new Random();
+         
         String[] wiseWords = new String[] {"You're a hard worker and you will do great on all the labs!", 
                 "Look how much java you learned this week! That's awesome!", 
                 "Keep up the good work!" ,
                 "You're cushing it!", "You're a coding rockstar!", 
                 "Keep coding!"};  
         int arrIndex = rand.nextInt(6);
+        System.out.println(arrIndex);
         return wiseWords[arrIndex];
     }
 
     }
 
     public static void printAns(String printAnswer){
-        System.out.println("ANSWER: " + printAnswer + "\n \n");
+        System.out.println( String.valueOf(printAnswer));
     }
 
     public static double inverse(double n1) {

Memory.java

         return mem;    
     }
     
-    public static double memUpdate(double n1) 
+    public static double memUpdate(double lastAns) 
     {
-        return n1;
+        return mem = lastAns;
     }
     
     public static double memClear()