diff --git a/n1/palindromeCheck.js b/n1/palindromeCheck.js
new file mode 100644
index 0000000..646033b
--- /dev/null
+++ b/n1/palindromeCheck.js
@@ -0,0 +1,32 @@
+function palindrome(str) {
+  let strSemEspacos = str.replace(/[^a-zA-Z0-9]/g, '').toLowerCase();
+  let tam = strSemEspacos.length
+  let m = Math.floor(tam/2);
+ 
+  let s;
+  let d;
+  if(tam%2==0){
+    s = m;
+    d = m-1;
+  }else{
+    s = m+1;
+    d = m-1;
+  }
+  let i = 0;
+  while(s < tam && d >= 0){
+    if(strSemEspacos[s]==strSemEspacos[d]){
+      i++;
+    }
+    s++;
+    d--;
+  }
+
+  if(i == m){
+    return true;
+  }else{
+    return false;
+  }
+}
+
+
+palindrome("eye");
diff --git a/n2/romanNumeral.js b/n2/romanNumeral.js
new file mode 100644
index 0000000..c1b9869
--- /dev/null
+++ b/n2/romanNumeral.js
@@ -0,0 +1,50 @@
+function convertToRoman(num) {
+  let final = '';
+  while(num > 0){
+    if(num >= 1000){
+      final +='M';
+      num -= 1000;
+    }else if(num >= 900){
+      final +='CM';
+      num -= 900;
+    }else if(num >= 500){
+      final +='D';
+      num -= 500;
+    }else if(num >= 400){
+      final +='CD';
+      num -= 400;
+    }else if(num >= 100){
+      final +='C';
+      num -= 100;
+    }else if(num >= 90){
+      final +='XC';
+      num -= 90;
+    }else if(num >= 50){
+      final +='L';
+      num -= 50;
+    }else if(num >= 40){
+      final +='XL';
+      num -= 40;
+    }else if(num >= 10){
+      final +='X';
+      num -= 10;
+    }else if(num >= 9){
+      final +='IX';
+      num -= 9;
+    }else if(num >= 5){
+      final +='V';
+      num -= 5;
+    }else if(num >= 4){
+      final +='IV';
+      num -= 1000;
+    }else if(num >= 1){
+      final +='I';
+      num -= 1;
+    }
+  }
+    return final;
+}
+  
+
+
+convertToRoman(36);
diff --git a/n3/telephoneValidador.js b/n3/telephoneValidador.js
new file mode 100644
index 0000000..b2430cb
--- /dev/null
+++ b/n3/telephoneValidador.js
@@ -0,0 +1,7 @@
+function telephoneCheck(str) {
+    let regex=/1?\s?((\d{3})|(\(\d{3}\)))[- ]?(\d{3})[- ]?(\d{4})/;
+
+  return regex.test(str) && str.match(regex)[0]===str;
+}
+
+telephoneCheck("555-555-5555");
diff --git a/n4/caesarsCipher.js b/n4/caesarsCipher.js
new file mode 100644
index 0000000..cd5dff3
--- /dev/null
+++ b/n4/caesarsCipher.js
@@ -0,0 +1,21 @@
+function rot13(str) {
+  var encryptedString = str.split('').map(char => {
+    var regex = /[A-Z]/;
+    if (regex.test(char)) {
+      let asciiValue = char.charCodeAt(0);
+      let final;
+      if ((asciiValue - 13)-65 < 0) {
+        final =(asciiValue-65)+78;
+      } else {
+        final = asciiValue - 13;
+      }
+      return String.fromCharCode(final);
+    }
+    return char;
+  }).join('');
+  console.log(encryptedString);
+
+  return encryptedString;
+}
+
+rot13("SERR PBQR PNZC");