diff --git a/oysteikt-calc/src/main/java/oysteikt/calc/CalcController.java b/oysteikt-calc/src/main/java/oysteikt/calc/CalcController.java
index 047b383..dd8ad13 100644
--- a/oysteikt-calc/src/main/java/oysteikt/calc/CalcController.java
+++ b/oysteikt-calc/src/main/java/oysteikt/calc/CalcController.java
@@ -74,60 +74,95 @@ public class CalcController {
     updateOperandsView();
   }
 
+  /* -------------------------------------------------------------------------- */
+  /*                             Exercise Functions                             */
+  /* -------------------------------------------------------------------------- */
+
   private void appendToOperand(String s) {
-    // TODO
+    this.setOperand(this.getOperandString() + s);
   }
 
   @FXML
   void handleDigit(ActionEvent ae) {
-    if (ae.getSource()instanceof Labeled l) {
-      // TODO append button label to operand
+    if (ae.getSource() instanceof Labeled l) {
+      this.appendToOperand(l.getText());
     }
   }
 
   @FXML
   void handlePoint() {
-    var operandString = getOperandString();
+    var operandString = this.getOperandString();
     if (operandString.contains(".")) {
-      // TODO remove characters after point
+      String stringBeforeDot = operandString.substring(0, operandString.indexOf('.') + 1);
+      this.setOperand(stringBeforeDot);
     } else {
-      // TODO append point
+      this.appendToOperand(".");
     }
   }
 
   @FXML
   void handleClear() {
-    // TODO clear operand
+    this.setOperand("");
+  }
+
+  private void pushOperandIfPossible() {
+    if (this.hasOperand()) {
+      this.calc.pushOperand(this.getOperand());
+      this.setOperand("");
+    }
   }
 
   @FXML
   void handleSwap() {
-    // TODO clear operand
+    this.pushOperandIfPossible();
+    this.calc.swap();
+    this.updateOperandsView();
   }
 
   private void performOperation(UnaryOperator<Double> op) {
-    // TODO
+    this.pushOperandIfPossible();
+    this.calc.performOperation(op);
+    this.updateOperandsView();
   }
 
-  private void performOperation(boolean swap, BinaryOperator<Double> op) {
-    if (hasOperand()) {
-      // TODO push operand first
+  // Removed `swap` parameter as described in 
+  // https://piazza.com/class/kssraggjcxm4at?cid=56
+  private void performOperation(BinaryOperator<Double> op) {
+    if (this.calc.getOperandCount() > 3) { // There should always be at least 3 times 0.0 in the calculator
+      this.pushOperandIfPossible();
+      this.calc.performOperation(op);
+      this.updateOperandsView();
     }
-    // TODO perform operation, but swap first if needed
   }
 
   @FXML
   void handleOpAdd() {
-    // TODO
+    this.performOperation((x, y) -> x + y);
   }
 
   @FXML
   void handleOpSub() {
-    // TODO
+    this.performOperation((x, y) -> x - y);
   }
 
   @FXML
   void handleOpMult() {
-    // TODO
+    this.performOperation((x, y) -> x * y);
+  }
+
+  @FXML
+  void handleOpDiv() {
+    this.performOperation((x, y) -> x / y);
+  }
+
+  @FXML
+  void handleOpRoot() {
+    this.performOperation((x) -> Math.sqrt(x));
+  }
+
+  @FXML
+  void handleOpPi() {
+    this.calc.pushOperand(Math.PI);
+    this.updateOperandsView();
   }
 }
diff --git a/oysteikt-calc/src/main/resources/oysteikt/calc/Calc.fxml b/oysteikt-calc/src/main/resources/oysteikt/calc/Calc.fxml
index 2fb7647..9ea6887 100644
--- a/oysteikt-calc/src/main/resources/oysteikt/calc/Calc.fxml
+++ b/oysteikt-calc/src/main/resources/oysteikt/calc/Calc.fxml
@@ -23,21 +23,21 @@
     GridPane.rowIndex="2" GridPane.columnIndex="1"/>
   <Button text="9" onAction="#handleDigit"
     GridPane.rowIndex="2" GridPane.columnIndex="2"/>
-  
+
   <Button text="4" onAction="#handleDigit"
     GridPane.rowIndex="3" GridPane.columnIndex="0"/>
   <Button text="5" onAction="#handleDigit"
     GridPane.rowIndex="3" GridPane.columnIndex="1"/>
   <Button text="6" onAction="#handleDigit"
     GridPane.rowIndex="3" GridPane.columnIndex="2"/>
-  
+
   <Button text="1" onAction="#handleDigit"
     GridPane.rowIndex="4" GridPane.columnIndex="0"/>
   <Button text="2" onAction="#handleDigit"
     GridPane.rowIndex="4" GridPane.columnIndex="1"/>
   <Button text="3" onAction="#handleDigit"
     GridPane.rowIndex="4" GridPane.columnIndex="2"/>
-  
+
   <Button text="0" onAction="#handleDigit"
     GridPane.rowIndex="5" GridPane.columnIndex="0"/>
   <Button text="." onAction="#handlePoint"
@@ -54,11 +54,10 @@
   <Button text="*" onAction="#handleOpMult"
     GridPane.rowIndex="6" GridPane.columnIndex="2"/>
 
-  <!-- TODO -->
-  <Button text="/"
+  <Button text="/" onAction="#handleOpDiv"
     GridPane.rowIndex="6" GridPane.columnIndex="3"/>
-  <Button text="√"
+  <Button text="√" onAction="#handleOpRoot"
     GridPane.rowIndex="7" GridPane.columnIndex="0"/>
-  <Button text="π"
+  <Button text="π" onAction="#handleOpPi"
     GridPane.rowIndex="7" GridPane.columnIndex="1"/>
 </GridPane>