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..57cdb71 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..f3ad5ba 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
@@ -3,7 +3,19 @@
 
 public class Task10 {
 
-    public static boolean containDigitTwo(int n) {
-        return false;
-    }
+    public static boolean containDigitTwo(int a) {
+        boolean flag = false;
+        int aLast;
+        if(a == 0)
+            flag = false;
+        while((a/10) > 0){
+            aLast = a%10;
+            a = a/10;
+            if((aLast == 2)|(a == 2)) {
+                flag = true;
+                break;
+            }
+        }
+        return flag;
+        }
 }
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..21708ca 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 +3,6 @@
 
 public class Task2 {
     public static int getMeters(int centimeters) {
-        return 0;
+        return centimeters/100;
     }
 }
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..64a362c 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;
+        if (((b >= a)&(b <= c))|((b >= c)&(b <= a)))
+            return true;
+        else  return false;
+
     }
 }
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..b0b0714 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 +4,15 @@
 public class Task4 {
 
     public static double getSumOfGreatest(double a, double b, double c) {
-        return 0;
+        double x1;
+        double x2;
+        if (a >=b){
+            x1 = a;
+        } else x1 = b;
+        if (b >= c){
+            x2 = b;
+        } else x2 = c;
+
+        return x1 + x2;
     }
 }
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..149dda6 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 +3,14 @@
 
 public class Task5 {
     public static double calculateA(double x, double y, double z) {
-        return 0;
+        double b = 1 + (Math.pow(z,2)/(3 + (Math.pow(z,2)/5)));
+        double up = (2*Math.sin(x-(Math.PI)/6)*b);
+        double down = 0.5 + Math.sin(y)*Math.sin(y);
+        return  up / down;
     }
 
     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..dd243b3 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
@@ -1,11 +1,22 @@
 package school.lemon.changerequest.java.introduction.hw1;
 
 public class Task6 {
-    public static double calculateS(double x) {
-        return 0d;
+
+    public int factorial(int n){
+        int result;
+        if (n==1) return 1;
+        result = factorial(n-1)*n;
+        return result;
+    }
+
+    public double calculateS(double x) {
+        double answ = 1;
+        for(int i=1; i<5; i++)
+            answ = answ + (Math.pow(x, i) / factorial(i));
+        return answ;
     }
 
     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..05c3262 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 +3,23 @@
 
 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..6f0ae45 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
@@ -1,7 +1,12 @@
 package school.lemon.changerequest.java.introduction.hw1;
 
 public class Task8 {
-    public static int calculateSum(int N) {
-        return 0;
+    public static double calculateSum(double N) {
+        double res = 0;
+        int i;
+        for(i=0; i <(N+1); i++)
+            res = res + Math.pow((N + i), 2);
+
+        return res;
     }
 }
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..99e6ca7 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 +3,16 @@
 public class Task9 {
 
     public static boolean isPowerOfThree(int n) {
-        return false;
+        boolean flag = true;
+        if(n == 0)
+            flag = false;
+        while(n > 1){
+            if((n % 3) > 0){
+                flag = false;
+                break;
+            } else n = n/3;
+        }
+
+        return flag;
     }
 }