diff --git a/src/part3/aufg4.java b/src/part3/aufg4.java
new file mode 100644
index 0000000..fc63bdd
--- /dev/null
+++ b/src/part3/aufg4.java
@@ -0,0 +1,31 @@
+package part3;
+
+public class aufg4 {
+    public static void main(String[] args){
+        int i = 5;
+        int j = 3;
+
+        boolean b = false;
+
+        // a) (!((i<j) && b))
+        // bool true
+
+        // b) i/j
+        // int 1
+
+        // c) (float) (i/j)
+        // float 1.6667 ?
+
+        // d) (float) i/j
+        // float 1.6667 ?
+
+        // e) (float) i / (float) j
+        // float 1.6667 ?
+
+        // f) ((i++ == 5) || (--i == 5))
+        // bool true
+
+        // g) ((i++ == 5) | (--i == 5))
+        // error ?
+    }
+}
diff --git a/src/part4/aufg1.java b/src/part4/aufg1.java
new file mode 100644
index 0000000..50726e1
--- /dev/null
+++ b/src/part4/aufg1.java
@@ -0,0 +1,20 @@
+package part4;
+
+public class aufg1 {
+    public static void main(String[] args){
+        int MAXIMUM = 42;
+
+        for(int i = 1; i < MAXIMUM; i++){
+            if(i % 2 == 0){
+                System.out.println(i);
+            }
+        }
+        System.out.println("=================");
+        System.out.println("=================");
+        for(int i = MAXIMUM; i > 1; i--){
+            if(i % 2 == 1){
+                System.out.println(i);
+            }
+        }
+    }
+}
diff --git a/src/part4/aufg2.java b/src/part4/aufg2.java
new file mode 100644
index 0000000..74d6d28
--- /dev/null
+++ b/src/part4/aufg2.java
@@ -0,0 +1,34 @@
+package part4;
+
+public class aufg2 {
+    public static void main(String[] args){
+        int sum = 0;
+
+        for(int i = 1; i<21; i++){
+            sum += i;
+            System.out.println("the sum of the first " + i + " integers is: " + sum);
+        }
+
+        System.out.println("========================================");
+
+        sum = 0;
+        int i = 1;
+
+        while(i<21){
+            sum += i;
+            System.out.println("the sum of the first " + i + " integers is: " + sum);
+            i++;
+        }
+
+        System.out.println("========================================");
+
+        sum = 0;
+        i = 0;
+
+        do{
+            sum += i;
+            System.out.println("the sum of the first " + i + " integers is: " + sum);
+            i++;
+        }while (i<21);
+    }
+}