diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task1.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task1.java
index 3bed9e0..2c16cee 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task1.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task1.java
@@ -3,6 +3,7 @@
 
 public class Task1 {
     public static double calculateP(double a) {
-        return 0;
+
+        return 4 * a;
     }
 }
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task10.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task10.java
index 1f87d43..d272add 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task10.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task10.java
@@ -4,6 +4,15 @@
 public class Task10 {
 
     public static boolean containDigitTwo(int n) {
+
+        while (n > 0) {
+            if (n % 10 == 2) {
+                return true;
+            }
+             n = n / 10;
+
+        }
+
         return false;
     }
 }
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task2.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task2.java
index a4578a5..06c4c69 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task2.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task2.java
@@ -3,6 +3,7 @@
 
 public class Task2 {
     public static int getMeters(int centimeters) {
-        return 0;
+
+        return centimeters / 100;
     }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task3.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task3.java
index 49f98de..bb97a35 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task3.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task3.java
@@ -2,6 +2,9 @@
 
 public class Task3 {
     public static boolean isBetween(int a, int b, int c) {
-        return false;
+
+        return  ((a <= b && b <= c) || (a >= b && b >= c));
+
     }
 }
+
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task4.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task4.java
index 1b2c077..a9ce944 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task4.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task4.java
@@ -4,6 +4,14 @@
 public class Task4 {
 
     public static double getSumOfGreatest(double a, double b, double c) {
-        return 0;
-    }
-}
+            if (a < b && b < c) {
+            return c + b;
+            }
+                 if (a > b && b > c) {
+                    return b + a;
+                 }
+                else {
+                    return a + c;
+                 }
+        }
+}
\ No newline at end of file
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task5.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task5.java
index 25bfde5..88331c8 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task5.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task5.java
@@ -3,10 +3,10 @@
 
 public class Task5 {
     public static double calculateA(double x, double y, double z) {
-        return 0;
+        return ((2 * Math.sin(x - Math.PI / 6) * calculateB(z)) / (1 / 2.0 + (Math.pow(Math.sin(y), 2))));
     }
 
     private static double calculateB(double z) {
-        return 0;
+        return 1 + (Math.pow(z, 2)) / (3 + ((Math.pow(z, 2)) / 5));
     }
 }
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task6.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task6.java
index 5db16c9..560a6ed 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task6.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task6.java
@@ -2,10 +2,20 @@
 
 public class Task6 {
     public static double calculateS(double x) {
-        return 0d;
+        return (1 + x + (Math.pow(x, 2)/factorial(2)) + (Math.pow(x, 3)/factorial(3)) + (Math.pow(x, 4)/factorial(4)));
+
+        }
+
+    private static int factorial(int n) {
+        int result = 1;
+        for (int i = n; i > 0; i--) {
+            result = result * i;
+            }
+            return result;
     }
 
     public static double calculateZ(double x, double y) {
-        return 0d;
+
+        return Math.sin(Math.pow(x, 3)) + Math.pow(Math.cos(y), 2);
     }
 }
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task7.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task7.java
index 7d39c57..4b68119 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task7.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task7.java
@@ -3,6 +3,33 @@
 
 public class Task7 {
     public static String getDayTitle(int dayIndex) {
-        return "";
+
+        switch (dayIndex)
+        {
+            case 1:
+                return "Monday";
+
+            case 2:
+                return "Tuesday";
+
+            case 3:
+                return  "Wednesday";
+
+            case 4:
+                return "Thursday";
+
+            case 5:
+                return "Friday";
+
+            case 6:
+                return "Saturday";
+
+            case 7:
+                return "Sunday";
+
+            default:
+                return  "error";
+        }
+
     }
 }
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task8.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task8.java
index 927306f..75ee594 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task8.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task8.java
@@ -2,6 +2,10 @@
 
 public class Task8 {
     public static int calculateSum(int N) {
-        return 0;
+        int result = 0;
+
+        for (int i = N; 2 * N >= i; i++)
+            result+= i*i;
+        return result;
     }
 }
diff --git a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task9.java b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task9.java
index f17d372..2ed062d 100644
--- a/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task9.java
+++ b/src/main/java/school/lemon/changerequest/java/introduction/hw1/Task9.java
@@ -3,6 +3,15 @@
 public class Task9 {
 
     public static boolean isPowerOfThree(int n) {
-        return false;
-    }
+
+        if (n <= 1){
+            return false;
+        }
+
+        while (n>1 && (n % 3) == 0) {
+            n = n / 3;
+        }
+            return n == 1;
+     }
 }
+