diff --git a/B12NumbersV3/B12Char.pde b/B12NumbersV3/B12Char.pde
index cb3b50f..165e73a 100644
--- a/B12NumbersV3/B12Char.pde
+++ b/B12NumbersV3/B12Char.pde
@@ -1,12 +1,14 @@
 class B12Char extends B12Digit{
+  String valid;
   char c;
   
   B12Char(char _c){
     super(0);
-    if(_c == '-' || _c == '.' || _c == ':'){
+    valid = "+-*/.:"; // Defines valid input characters
+    if(inStr(_c)){
       c = _c;
     }else{ 
-      throw new IllegalArgumentException("B12Char only accepts \'-\', \'.\', and ':'"); 
+      throw new IllegalArgumentException("B12Char only accepts \'+ - * / . :'"); 
     }
   }
   
@@ -17,8 +19,14 @@ class B12Char extends B12Digit{
     strokeWeight(1);
     
     switch(c) {
+      case '+':
+        lineMinus(); linePlus(); break;
       case '-':
         lineMinus(); break;
+      case '*':
+        lineTimes(); break;
+      case '/':
+        lineMinus(); dotsDiv(); break;
       case '.':
         strokeWeight(2); period(); break;
       case ':':
@@ -28,7 +36,20 @@ class B12Char extends B12Digit{
     popMatrix();
   }
   
+  void lineTimes(){ line(4,-7,8,-3); line(4,-3,8,-7); }
+  void dotsDiv(){ point(6,-8); point(6,-2); }
   void lineMinus(){ line(3,-5,9,-5); }
+  void linePlus(){ line(6,-8,6,-2); }
   void period(){ point(5,0); }
   void colon(){ point(5,-2); point(5,-8); }
+  
+  boolean inStr(char _c){
+    try{
+      int x = valid.indexOf(_c);
+      return true;
+    }
+    catch (Exception e){
+      return false;
+    }
+  }
 }
diff --git a/B12NumbersV3/B12Math.pde b/B12NumbersV3/B12Math.pde
new file mode 100644
index 0000000..7a96bbd
--- /dev/null
+++ b/B12NumbersV3/B12Math.pde
@@ -0,0 +1,15 @@
+class B12Math {
+  ArrayList <B12Digit> expression;
+  
+  B12Math(){
+    expression = new ArrayList<B12Digit>();;
+  }
+  
+  void delete(int pos){
+    expression.remove(pos);
+  }
+  
+  void evaluate(){
+    //TODO set expression to evaluation of expression
+  }
+}
diff --git a/B12NumbersV3/B12NumbersV3.pde b/B12NumbersV3/B12NumbersV3.pde
index 12f56a3..1348496 100644
--- a/B12NumbersV3/B12NumbersV3.pde
+++ b/B12NumbersV3/B12NumbersV3.pde
@@ -13,19 +13,25 @@
 public static int DECIMAL = 65;
 
 Clock clock;
+B12Char p;
+B12Char t;
 
 void setup(){
   size(400,400);
   clock = new Clock(new STime48());
   println("waiting");
+  p = new B12Char('+');
+  t = new B12Char('/');
 }
 
 void draw(){
   background(196);
   translate(width/2,height/2);
-  scale(1);
+  scale(2);
   point(0,0);
   clock.display();
+  //p.display();
+  t.display();
 }
 
 void mouseClicked(){
diff --git a/B12NumbersV3/MathDisplay.pde b/B12NumbersV3/MathDisplay.pde
new file mode 100644
index 0000000..3ff4682
--- /dev/null
+++ b/B12NumbersV3/MathDisplay.pde
@@ -0,0 +1,16 @@
+class MathDisplay{
+  B12Math math;
+  
+  
+  MathDisplay(B12Math _math){
+    math = _math;
+    digits = new ArrayList<B12Digit>();
+  }
+  
+  // TODO take expression from math and display it in whatever state it is in
+  void display(){
+    for(int i = 0; i < math.expression.size(); i++){
+      
+    }
+  }
+}
diff --git a/B12NumbersV3/MathPad.pde b/B12NumbersV3/MathPad.pde
new file mode 100644
index 0000000..f308113
--- /dev/null
+++ b/B12NumbersV3/MathPad.pde
@@ -0,0 +1,16 @@
+class MathPad{
+  B12Math math;
+  
+  MathPad(B12Math _math){
+    math = _math;
+  }
+  
+  // TODO draw a grid for buttons
+  // TODO draw characters in grid
+  // TODO detect mousepresses on the buttons (maybe a global mouse handler?)
+  // TODO send characters to math
+  
+  void addchar(){
+    math.expression.add(new B12Char('/'));
+  }
+}
diff --git a/B12NumbersV3/Time.pde b/B12NumbersV3/Time.pde
deleted file mode 100644
index 1caeac9..0000000
--- a/B12NumbersV3/Time.pde
+++ /dev/null
@@ -1,96 +0,0 @@
-/*class Time extends Thread{
-  PVector pos;
-  B12Int hours;
-  B12Int minutes;
-  B12Int seconds;
-  B12Char sep;
-  B12Int fill;
-  int tmillis;
-  boolean initialized;
-  
-  Time(Time48 t48){ // TODO refactor time class
-    pos = new PVector(0,0);
-    hours = new B12Int(0);
-    minutes = new B12Int(0);
-    seconds = new B12Int(0);
-    sep = new B12Char(':');
-    fill = new B12Int(0);
-    
-    hours.setMinLen(2);
-    minutes.setMinLen(2);
-    seconds.setMinLen(2);
-    
-    initialized = false;
-    this.start();
-    //thread("this.runTime");
-  }
-  
-  PVector getPos(){ return pos; }
-  void setPos(PVector _pos){ pos = _pos.copy(); }
-  void setPos(float _x, float _y){ pos = new PVector(_x,_y); }
-  
-  void setTime(int _h, int _m, int _s, boolean twelve){
-    if(twelve){
-      tmillis = int(((_h*48*48 + _m*48 + _s)*1562.5) - millis());
-    }else{
-      tmillis = (_h*60*60*1000 + _m*60*1000 + _s*1000) - millis();
-    }
-    initialized = true;
-  }
-  
-  public void run(){
-    while(true){
-      if(!initialized){ sync(); }
-      if(tmillis + millis() > 86400000){ tmillis -= 86400000; } // Fall over at 00:00
-      int sec48 = int((tmillis + millis()) / 1562.5);
-      int min48 = sec48 / 48;
-      int hour48 = min48 / 48;
-      sec48 -= min48 * 48;
-      min48 -= hour48 * 48;
-      //println(hour48 + ":" + min48 + ":" + sec48);
-      hours.setValue(hour48);
-      minutes.setValue(min48);
-      seconds.setValue(sec48);
-    }
-  }
-  
-  public void syncTime(){ initialized = false; } // Allows syncing after time starts running
-  private void sync(){
-    int sec = second();
-    tmillis = 0;
-    while(true){
-      if(sec != second()){
-        tmillis = second()*1000 + minute()*60*1000 + hour()*60*60*1000;
-        initialized = true;
-        break;
-      }
-    }
-  }
-  
-  void display(){
-    if(initialized){
-      // Position
-      
-      hours.setPos(-64, 0);
-      minutes.setPos(-32, 0);
-      seconds.setPos(0,0);
-      B12Char c1 = new B12Char(':');
-      B12Char c2 = new B12Char(':');
-      c1.setRefPos(-34,0);
-      c2.setRefPos(-66,0);
-      
-      // Display
-      pushMatrix();
-      translate(pos.x,pos.y);
-      hours.display();
-      c2.display();
-      minutes.display();
-      c1.display();
-      seconds.display();
-      popMatrix();
-      //print(seconds.getValue());
-    }else{
-      text("initializing " + second(),pos.x,pos.y);
-    }
-  }
-}*/