diff --git a/task01/src/com/example/task01/Task01Main.java b/task01/src/com/example/task01/Task01Main.java
index 7efef9a8..f925d982 100644
--- a/task01/src/com/example/task01/Task01Main.java
+++ b/task01/src/com/example/task01/Task01Main.java
@@ -16,6 +16,15 @@ public static void main(String[] args) throws IOException {
 
     public static int checkSumOfStream(InputStream inputStream) throws IOException {
         // your implementation here
-        return 0;
+        if (inputStream == null) throw new IllegalArgumentException();
+
+        int sum = 0;
+        int currentByte;
+
+        while ((currentByte = inputStream.read()) != -1) {
+            sum = Integer.rotateLeft(sum, 1) ^ currentByte;
+        }
+
+        return sum;
     }
 }
diff --git a/task02/src/com/example/task02/Task02Main.java b/task02/src/com/example/task02/Task02Main.java
index 865ea659..93ee8bd2 100644
--- a/task02/src/com/example/task02/Task02Main.java
+++ b/task02/src/com/example/task02/Task02Main.java
@@ -9,5 +9,23 @@ public static void main(String[] args) throws IOException {
         // - направить стандартный вывод программы в файл output.test
         // - запустить программу
         // - и сравнить получившийся файл output.test с expected.test
+        int prevByte = -1;
+        int currentByte;
+
+        while ((currentByte = System.in.read()) != -1) {
+            if (prevByte == 13 && currentByte == 10) {
+                System.out.write(10);
+                prevByte = -1;
+            } else {
+                if (prevByte != -1) {
+                    System.out.write(prevByte);
+                }
+                prevByte = currentByte;
+            }
+        }
+        if (prevByte != -1) {
+            System.out.write(prevByte);
+        }
+        System.out.flush();
     }
 }
diff --git a/task03/src/com/example/task03/Task03Main.java b/task03/src/com/example/task03/Task03Main.java
index 332e0366..1d9b370d 100644
--- a/task03/src/com/example/task03/Task03Main.java
+++ b/task03/src/com/example/task03/Task03Main.java
@@ -1,7 +1,6 @@
 package com.example.task03;
 
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
 import java.nio.charset.Charset;
 
 public class Task03Main {
@@ -16,6 +15,19 @@ public static void main(String[] args) throws IOException {
 
     public static String readAsString(InputStream inputStream, Charset charset) throws IOException {
         // your implementation here
-        return "";
+
+        if (inputStream == null || charset == null) {
+            throw new IllegalArgumentException();
+        }
+
+        InputStreamReader reader = new InputStreamReader(inputStream, charset);
+        BufferedReader bufferedReader = new BufferedReader(reader);
+        StringBuilder result = new StringBuilder();
+        String currentLine;
+
+        while ((currentLine = bufferedReader.readLine()) != null) {
+            result.append(currentLine);
+        }
+        return result.toString();
     }
 }
diff --git a/task04/src/com/example/task04/Task04Main.java b/task04/src/com/example/task04/Task04Main.java
index 4236c2e7..f7fdc0a2 100644
--- a/task04/src/com/example/task04/Task04Main.java
+++ b/task04/src/com/example/task04/Task04Main.java
@@ -1,6 +1,8 @@
 package com.example.task04;
 
 import java.io.IOException;
+import java.util.Locale;
+import java.util.Scanner;
 
 public class Task04Main {
     public static void main(String[] args) throws IOException {
@@ -8,7 +10,17 @@ public static void main(String[] args) throws IOException {
         // - направить файл input.test в стандартный ввод программы (в настройках запуска программы в IDE или в консоли)
         // - запустить программу
         // - проверить, что получилось 351.731900
+        Scanner scanner = new Scanner(System.in);
+        double sum = 0.0;
+        while (scanner.hasNext()) {
+            String token = scanner.next();
+            try {
+                double number = Double.parseDouble(token);
+                sum += number;
+            } catch (NumberFormatException e) {
 
-        System.out.println("0.0");
+            }
+        }
+        System.out.printf(Locale.US,"%.6f", sum);
     }
 }