diff --git a/staff/carlos-bock/chain-characters/index.js b/staff/carlos-bock/chain-characters/index.js
index 2e6995fc..c1d26bc5 100644
--- a/staff/carlos-bock/chain-characters/index.js
+++ b/staff/carlos-bock/chain-characters/index.js
@@ -5,8 +5,9 @@ const concat = require("./concat.js")
 const endsWith = require("./endsWith.js")
 const includes = require("./includes.js")
 const indexOf = require("./indexOf.js")
+const replace = require("./replace.js")
 const repeat = require("./repeat.js")
-
+const slice = require("./slice.js")
 
 const split = require("./split.js")
 
@@ -22,7 +23,9 @@ ChainCharacters.prototype.concat = concat;
 ChainCharacters.prototype.endsWith = endsWith;
 ChainCharacters.prototype.includes = includes;
 ChainCharacters.prototype.indexOf = indexOf;
+ChainCharacters.prototype.replace = replace;
 ChainCharacters.prototype.repeat = repeat;
+ChainCharacters.prototype.slice = slice;
 
 
 ChainCharacters.prototype.split = split;
diff --git a/staff/carlos-bock/chain-characters/index.test.js b/staff/carlos-bock/chain-characters/index.test.js
index 3195dc9f..7f74f487 100644
--- a/staff/carlos-bock/chain-characters/index.test.js
+++ b/staff/carlos-bock/chain-characters/index.test.js
@@ -4,8 +4,9 @@ require("./concat.test.js");
 require("./endsWith.test.js");
 require("./includes.test.js");
 require("./indexOf.test.js");
+require("./replace.test.js");
 require("./repeat.test.js");
-
+require("./slice.test.js");
 
 require("./split.test.js");
 
diff --git a/staff/carlos-bock/chain-characters/replace.js b/staff/carlos-bock/chain-characters/replace.js
index b76f2aca..352e6e0f 100644
--- a/staff/carlos-bock/chain-characters/replace.js
+++ b/staff/carlos-bock/chain-characters/replace.js
@@ -6,9 +6,10 @@
 //si parametro === a string[i] entonces newString = string[string.length-index] + parametro + string[segunda mitad]
 //resolver primero string al principio 
 
+const ChainCharacters = require("./constructor");
 
-function replace(string, oldPhrase, newPhrase) {
-    const oldString = string;
+function replace(oldPhrase, newPhrase) { //removed string parameter
+    const oldString = this.value;
     let result = false;
     let newString ="";
 
@@ -19,7 +20,7 @@ function replace(string, oldPhrase, newPhrase) {
             let solution = true;
 
          for (let j = 0; j < oldPhrase.length; j++) {
-            if (string[i + j] !== oldPhrase[j]){   
+            if (this.value[i + j] !== oldPhrase[j]){   
                solution = false;
                break;                
             } 
@@ -31,29 +32,11 @@ function replace(string, oldPhrase, newPhrase) {
             i += oldPhrase.length - 1;
             result = true;
         } else {
-            newString += string[i];
+            newString += this.value[i];
         }
     }
 
-    return newString;
+    return new ChainCharacters(newString);
 }
 
-const aString = "My favorite color is blue";
-const oldWord = "blue";
-const newWord = "red";
-
-const stringB = "Cual es el mejor bootcamp";
-const pregunta = "Cual";
-const respuesta = "ISDI";
-
-const result1 = replace(aString, oldWord, newWord);
-console.assert(result1 === aString.replace(oldWord, newWord),{
-  result: result1,
-  message: "Test 1 No pasado ",
-});
-
-const result2 = replace(stringB, pregunta, respuesta);
-console.assert(result2 === stringB.replace(pregunta, respuesta),{
-  result: result2,
-  message: "Test 1 No pasado ",
-});
\ No newline at end of file
+module.exports = replace;
\ No newline at end of file
diff --git a/staff/carlos-bock/chain-characters/replace.test.js b/staff/carlos-bock/chain-characters/replace.test.js
new file mode 100644
index 00000000..23687d27
--- /dev/null
+++ b/staff/carlos-bock/chain-characters/replace.test.js
@@ -0,0 +1,23 @@
+
+
+const ChainCharacters = require("./");
+
+const aString = "My favorite color is blue";
+const oldWord = "blue";
+const newWord = "red";
+
+const stringB = "Cual es el mejor bootcamp";
+const pregunta = "Cual";
+const respuesta = "ISDI";
+
+const result1 = new ChainCharacters(aString).replace(oldWord, newWord);
+console.assert(result1.value === aString.replace(oldWord, newWord),{
+  result: result1,
+  message: "Test 1 No pasado ",
+});
+
+const result2 = new ChainCharacters(stringB).replace(pregunta, respuesta);
+console.assert(result2.value === stringB.replace(pregunta, respuesta),{
+  result: result2,
+  message: "Test 1 No pasado ",
+});
\ No newline at end of file
diff --git a/staff/carlos-bock/chain-characters/slice.js b/staff/carlos-bock/chain-characters/slice.js
index ce0cf6e0..acf388a9 100644
--- a/staff/carlos-bock/chain-characters/slice.js
+++ b/staff/carlos-bock/chain-characters/slice.js
@@ -4,24 +4,15 @@
 //si hay dos parametros usa el primer indice hasta llegar al segundo para crear el nuevo string
 //si los indices sone negativos se cuentan desde el final del string original. 
 
-function slice(string, index1, index2) {
+const ChainCharacters = require("./constructor");
+
+function slice(index1, index2) {
   let newString = "";
 
   for (let i = index1; i < index2; i++) {
-          newString += string[i]; 
+          newString += this.value[i]; 
       }
-  return newString;
+  return new ChainCharacters(newString);
 }
 
-
-
-const string1 = "Madrid es la mejor ciudad del mundo."
-const indexOne = 6;
-const indexTwo = 12;
-
-
-const result1 = slice(string1, 1, 3 );
-console.assert(result1 === string1.slice(1, 3),{
-  result: result1,
-  message: "Test 1 No pasado ",
-});
\ No newline at end of file
+module.exports = slice
\ No newline at end of file
diff --git a/staff/carlos-bock/chain-characters/slice.test.js b/staff/carlos-bock/chain-characters/slice.test.js
new file mode 100644
index 00000000..38dfa4de
--- /dev/null
+++ b/staff/carlos-bock/chain-characters/slice.test.js
@@ -0,0 +1,11 @@
+
+
+const ChainCharacters = require("./");
+
+const string1 = "Madrid es la mejor ciudad del mundo."
+
+const result1 = new ChainCharacters(string1).slice(1, 3 );
+console.assert(result1.value === string1.slice(1, 3),{
+  result: result1,
+  message: "Test 1 No pasado ",
+});
\ No newline at end of file