diff --git a/src/advanced/strings-adv.js b/src/advanced/strings-adv.js
index 1b1eb60..e57699f 100644
--- a/src/advanced/strings-adv.js
+++ b/src/advanced/strings-adv.js
@@ -3,25 +3,25 @@ const cityStr = 'City'
 const shoppingList = 'apples, bananas, oranges, grapes'
 
 // TODO get the INDEX of the character where 'York' word is found in the city variable
-const cityIndex = 0
+const cityIndex = city.indexOf('York')
 
 // TODO - get the substring "York" from the city variable
-const citySubstring = ''
+const citySubstring = city.substring(cityIndex)
 
 // TODO = replace 'York' with 'Delhi'
-const cityReplaced = ''
+const cityReplaced = city.replace('York', 'Delhi')
 
 // TODO - check if city starts with 'New' and ends with 'York'
-const cityStartsWith = false
-const cityEndsWith = false
+const cityStartsWith = city.startsWith('New')
+const cityEndsWith = city.endsWith('York')
 
 // TODO - split the shopping list into an array of items without spaces
 // hint (you might want to replace first, then split)
-const shoppingListArray = []
+const shoppingListArray = shoppingList.replace(/,\s*/g, ',').split(',')
 
 // TODO - concatenate two strings using the `${var}` syntax
 // make cityStrConcat equal to 'New York City'
-const cityStrConcat = ''
+const cityStrConcat = city.concat(' ' + `${cityStr}`)
 
 module.exports = {
   cityIndex,
diff --git a/src/extensions/more-data-types.js b/src/extensions/more-data-types.js
index 64cde7b..73c06c2 100644
--- a/src/extensions/more-data-types.js
+++ b/src/extensions/more-data-types.js
@@ -1,22 +1,22 @@
 // TODO: Replace the empty string in the lines below using Javascript with the correct data types
 
 // 1. Set this variable to be null
-const nullVariable = ''
+const nullVariable = null
 
 // 2. Set this variable to be true
-const trueVariable = ''
+const trueVariable = true
 
 // 2. Set this variable to be the opposite of the trueVariable (ie. false);
-const falseVariable = ''
+const falseVariable = !trueVariable
 
 // 3. Set this variable to be undefined
-const undefinedVariable = ''
+const undefinedVariable = undefined
 
 // 4. get the typeof each of the above variables
 // hint you can use typeof variable to return a string of the variable type
-const typeOfTrueVariable = ''
-const typeOfFalseVariable = ''
-const typeOfUndefinedVariable = ''
+const typeOfTrueVariable = typeof trueVariable
+const typeOfFalseVariable = typeof falseVariable
+const typeOfUndefinedVariable = typeof undefinedVariable
 
 // do not edit the exported object.
 module.exports = {
diff --git a/src/numbers.js b/src/numbers.js
index ee37fa1..19790e4 100644
--- a/src/numbers.js
+++ b/src/numbers.js
@@ -12,22 +12,22 @@ const numThree = 32
 //       NOT myAnswer = 336
 
 // 1. Set this variable to numOne added to numTwo
-const numOnePlusNumTwo = NaN
+const numOnePlusNumTwo = numTwo + numOne
 
 // 2. Set this variable to numThree multiplied by numTwo
-const numThreeTimesNumTwo = NaN
+const numThreeTimesNumTwo = numThree * numTwo
 
 // 3. Set this variable to numThree divided by numOne
-const numThreeDividedByNumOne = NaN
+const numThreeDividedByNumOne = numThree / numOne
 
 // 4. Set this variable to numThree minus numOne
-const numThreeMinusNumOne = NaN
+const numThreeMinusNumOne = numThree - numOne
 
 // 5. Set this variable to the sum of numOne, numTwo and numThree
-const sum = NaN
+const sum = numOne + numTwo + numThree
 
 // 6. Set this variable to the sum of (numOne, numTwo, numThree) divided by numOne
-const numBytes = NaN
+const numBytes = sum / numOne
 
 // do not edit the exported object.
 module.exports = {
diff --git a/src/strings.js b/src/strings.js
index a846086..515f29c 100644
--- a/src/strings.js
+++ b/src/strings.js
@@ -13,16 +13,16 @@ const secondName = 'Smith'
 //       NOT twoJanes = "JaneJane"
 
 // 1. Set this variable to firstName and secondName concatenated
-const fullName = null
+const fullName = firstName + ' ' + secondName
 
 // 2. Set this variable to the 10th character of the alphabet variable
-const tenthCharacterOfAlphabet = null
+const tenthCharacterOfAlphabet = alphabet.charAt(9)
 
 // 3. Set this variable by calling a method on the alphabet variable to transform it to lower case
-const lowerCaseAlphabet = null
+const lowerCaseAlphabet = alphabet.toLowerCase()
 
 // 4. Set this variable by using a property on the alphabet variable to get it's length
-const numberOfLettersInAlphabet = null
+const numberOfLettersInAlphabet = alphabet.length
 
 // do not edit the exported object.
 module.exports = {