diff --git a/I.pass-tests/01-add-one/add-one.js b/I.pass-tests/01-add-one/add-one.js
index d955394c..371394a1 100644
--- a/I.pass-tests/01-add-one/add-one.js
+++ b/I.pass-tests/01-add-one/add-one.js
@@ -1 +1,6 @@
-module.exports = function(numbers) {};
+module.exports = function(numbers) {
+  if(numbers.length === 0){
+    throw new Error()
+  }
+  return numbers.map((n)=> n + 1)
+};
\ No newline at end of file
diff --git a/I.pass-tests/01-add-one/add-one.test.js b/I.pass-tests/01-add-one/add-one.test.js
index 5ed6be59..4601b596 100644
--- a/I.pass-tests/01-add-one/add-one.test.js
+++ b/I.pass-tests/01-add-one/add-one.test.js
@@ -1,12 +1,19 @@
 var addOne = require("./add-one.js");
 
 test("Add 1 to each item in myArray", function() {
-  var myArray = [31, 57, 12, 5];
+  var myArray = [-1, 57, 12, 5];
 
-  var unchanged = [31, 57, 12, 5];
-  var expected = [32, 58, 13, 6];
+
+  var unchanged = [-1, 57, 12, 5];
+  var expected = [0, 58, 13, 6];
   var output = addOne(myArray);
 
+
   expect(output).toEqual(expected);
   expect(myArray).toEqual(unchanged);
 });
+
+test('should throw error if there are no numbers in the array', () => {
+  const myArray = []
+  expect(() => addOne(myArray)).toThrow(Error)
+})
\ No newline at end of file
diff --git a/I.pass-tests/02-get-word-lengths/get-word-lengths.js b/I.pass-tests/02-get-word-lengths/get-word-lengths.js
index d7560427..1be6b6d7 100644
--- a/I.pass-tests/02-get-word-lengths/get-word-lengths.js
+++ b/I.pass-tests/02-get-word-lengths/get-word-lengths.js
@@ -1,3 +1,13 @@
-var getWordLengths = function(someWords) {};
+var getWordLengths = function(someWords) {
+  if(someWords.length === 0){
+    throw new Error()
+  }
+  return someWords.map((word)=> {
+    if(typeof word != 'string'){
+      throw new Error()
+    }
+    return word.split('').length
+  })
+};
 
-module.exports = getWordLengths;
+module.exports = getWordLengths;
\ No newline at end of file
diff --git a/I.pass-tests/02-get-word-lengths/get-word-lengths.test.js b/I.pass-tests/02-get-word-lengths/get-word-lengths.test.js
index 3a43925e..0b8416a9 100644
--- a/I.pass-tests/02-get-word-lengths/get-word-lengths.test.js
+++ b/I.pass-tests/02-get-word-lengths/get-word-lengths.test.js
@@ -4,6 +4,17 @@ test("Get word lengths", function() {
   var words = ["sun", "potato", "roundabout", "pizza"];
   var expected = [3, 6, 10, 5];
 
+
   var output = wordLengths(words);
   expect(output).toEqual(expected);
 });
+
+test("If there is an element that is not a string", function(){
+  const words = [123, "string"]
+  expect(() => wordLengths(words).toThrow(Error))
+})
+
+test("If array of words is empty", function(){
+  const words = []
+  expect(() => wordLengths(words)).toThrow(Error)
+})
\ No newline at end of file
diff --git a/I.pass-tests/03-sum-numbers/add-numbers.js b/I.pass-tests/03-sum-numbers/add-numbers.js
index 09b2a134..e56d5ce7 100644
--- a/I.pass-tests/03-sum-numbers/add-numbers.js
+++ b/I.pass-tests/03-sum-numbers/add-numbers.js
@@ -1,2 +1,12 @@
-function addNumbers(numbers) {}
+function addNumbers(numbers) {
+  if(numbers.length===0){
+    throw new Error()
+  }
+  return numbers.reduce((acc,current)=> {
+    if (typeof current != 'number'){
+      throw new Error()
+    }  
+    return acc+current
+  })
+}
 module.exports = addNumbers;
diff --git a/I.pass-tests/03-sum-numbers/add-numbers.test.js b/I.pass-tests/03-sum-numbers/add-numbers.test.js
index 8807a720..28bc38fc 100644
--- a/I.pass-tests/03-sum-numbers/add-numbers.test.js
+++ b/I.pass-tests/03-sum-numbers/add-numbers.test.js
@@ -8,3 +8,13 @@ test("Add all numbers", function() {
 
   expect(output).toEqual(expected);
 });
+
+test("Check if array is empty", function() {
+  var numbers = [];
+  expect(()=>addAllnumbers(numbers)).toThrow(Error);
+});
+
+test("If there is an element that is not a number", function(){
+  const words = [123, "string"]
+  expect(() => wordLengths(words).toThrow(Error))
+})