diff --git a/index.js b/index.js
index 3df06ec1..8c94454d 100644
--- a/index.js
+++ b/index.js
@@ -8,8 +8,14 @@
  */
 function trimProperties(obj) {
   // ✨ implement
+  const result = {}
+  for (let key in obj) {
+    result[key] = obj[key].trim(); //not sure if call key or prop
+  }
+  return result;
 }
 
+
 /**
  * [Exercise 2] trimPropertiesMutation trims in place the properties of an object
  * @param {object} obj - an object with properties that are strings
@@ -20,6 +26,10 @@ function trimProperties(obj) {
  */
 function trimPropertiesMutation(obj) {
   // ✨ implement
+  for (let key in obj) {
+    obj[key] = obj[key].trim(); //not sure if call key or prop
+  }
+  return obj;
 }
 
 /**
@@ -32,6 +42,13 @@ function trimPropertiesMutation(obj) {
  */
 function findLargestInteger(integers) {
   // ✨ implement
+ let largest = 0;
+  for (let i = 0; i < integers.length; i++) {
+    if (integers[i].integer > largest) {
+      largest = integers[i].integer;
+    }
+  }
+  return largest;
 }
 
 class Counter {
@@ -41,6 +58,7 @@ class Counter {
    */
   constructor(initialNumber) {
     // ✨ initialize whatever properties are needed
+    this.count = initialNumber;
   }
 
   /**
@@ -57,6 +75,11 @@ class Counter {
    */
   countDown() {
     // ✨ implement
+    if (this.count > 0) {
+      return this.count--;
+    }
+    return this.count;
+
   }
 }
 
@@ -66,6 +89,8 @@ class Seasons {
    */
   constructor() {
     // ✨ initialize whatever properties are needed
+    this.seasons = ["summer", "fall", "winter", "spring"];
+    this.currentSeason = 0
   }
 
   /**
@@ -82,6 +107,13 @@ class Seasons {
    */
   next() {
     // ✨ implement
+    const result = this.seasons[this.currentSeason];
+    if (this.currentSeason === 3) {
+      this.currentSeason = 0
+    } else {
+      this.currentSeason++;
+    } 
+    return result;
   }
 }
 
@@ -95,6 +127,9 @@ class Car {
   constructor(name, tankSize, mpg) {
     this.odometer = 0 // car initilizes with zero miles
     this.tank = tankSize // car initiazes full of gas
+    this.mpg = mpg // car initiazes with mpg
+    this.name = name // car initiazes with name
+    this.tankSize = tankSize
     // ✨ initialize whatever other properties are needed
   }
 
@@ -113,7 +148,16 @@ class Car {
    */
   drive(distance) {
     // ✨ implement
-  }
+    const milesCanDrive = this.tank * this.mpg;
+    if (milesCanDrive >= distance) {
+      this.odometer += distance;
+      this.tank -= (distance / this.mpg);
+    } else {
+      this.odometer += milesCanDrive;
+      this.tank = 0;
+    }
+    return this.odometer; 
+  } 
 
   /**
    * [Exercise 6C] Adds gallons to the tank
@@ -128,6 +172,13 @@ class Car {
    */
   refuel(gallons) {
     // ✨ implement
+    const gallonsCanFit = this.tankSize - this.tank;
+    if (gallonsCanFit >= gallons) {
+      this.tank += gallons;
+    } else {
+      this.tank = this.tankSize;
+    }
+    return this.drive(this.tank * this.mpg);
   }
 }
 
@@ -146,6 +197,11 @@ class Car {
  */
 function isEvenNumberAsync(number) {
   // ✨ implement
+  if (number % 2 === 0) {
+    return Promise.resolve(true);
+  } else {
+    return Promise.resolve(false);
+  }
 }
 
 module.exports = {
@@ -156,4 +212,4 @@ module.exports = {
   Counter,
   Seasons,
   Car,
-}
+};
diff --git a/index.test.js b/index.test.js
index cfb0a0b3..bc75fbf7 100644
--- a/index.test.js
+++ b/index.test.js
@@ -8,16 +8,37 @@ describe('[Exercise 1] trimProperties', () => {
     const actual = utils.trimProperties(input)
     expect(actual).toEqual(expected)
   })
-  // test('[2] returns a copy, leaving the original object intact', () => {})
+  test('[2] returns a copy, leaving the original object intact', () => {
+    const input = { foo: '  foo ', bar: 'bar ', baz: ' baz' }
+    utils.trimProperties(input)
+    expect(input).toEqual({ foo: '  foo ', bar: 'bar ', baz: ' baz' })
+  })
 })
 
 describe('[Exercise 2] trimPropertiesMutation', () => {
-  // test('[3] returns an object with the properties trimmed', () => {})
-  // test('[4] the object returned is the exact same one we passed in', () => {})
+  test('[3] returns an object with the properties trimmed', () => {
+    // EXAMPLE
+    const input = { foo: '  foo ', bar: 'bar ', baz: ' baz' }
+    const expected = { foo: 'foo', bar: 'bar', baz: 'baz' }
+    const actual = utils.trimProperties(input)
+    expect(actual).toEqual(expected)
+  })
+
+  test('[4] the object returned is the exact same one we passed in', () => {
+    const input = { foo: '  foo ', bar: 'bar ', baz: ' baz' }
+    const actual = utils.trimPropertiesMutation(input)
+    expect(actual).toBe(input)
+  })
 })
 
 describe('[Exercise 3] findLargestInteger', () => {
-  // test('[5] returns the largest number in an array of objects { integer: 2 }', () => {})
+  test('[5] returns the largest number in an array of objects { integer: 2 }', () => {
+    // EXAMPLE
+    const input = [{ integer: 1 }, { integer: 3 }, { integer: 2 }]
+    const expected = 3
+    const actual = utils.findLargestInteger(input)
+    expect(actual).toEqual(expected)
+  })
 })
 
 describe('[Exercise 4] Counter', () => {
@@ -25,9 +46,20 @@ describe('[Exercise 4] Counter', () => {
   beforeEach(() => {
     counter = new utils.Counter(3) // each test must start with a fresh couter
   })
-  // test('[6] the FIRST CALL of counter.countDown returns the initial count', () => {})
-  // test('[7] the SECOND CALL of counter.countDown returns the initial count minus one', () => {})
-  // test('[8] the count eventually reaches zero but does not go below zero', () => {})
+  test('[6] the FIRST CALL of counter.countDown returns the initial count', () => {
+    expect(counter.countDown()).toEqual(3)
+  })
+  test('[7] the SECOND CALL of counter.countDown returns the initial count minus one', () => {
+    counter.countDown()
+    expect(counter.countDown()).toEqual(2)
+  })
+  test('[8] the count eventually reaches zero but does not go below zero', () => {
+    counter.countDown()
+    counter.countDown()
+    counter.countDown() 
+    counter.countDown()
+    expect(counter.countDown()).toEqual(0)
+  })
 })
 
 describe('[Exercise 5] Seasons', () => {
@@ -35,12 +67,37 @@ describe('[Exercise 5] Seasons', () => {
   beforeEach(() => {
     seasons = new utils.Seasons() // each test must start with fresh seasons
   })
-  // test('[9] the FIRST call of seasons.next returns "summer"', () => {})
-  // test('[10] the SECOND call of seasons.next returns "fall"', () => {})
-  // test('[11] the THIRD call of seasons.next returns "winter"', () => {})
-  // test('[12] the FOURTH call of seasons.next returns "spring"', () => {})
-  // test('[13] the FIFTH call of seasons.next returns again "summer"', () => {})
-  // test('[14] the 40th call of seasons.next returns "spring"', () => {})
+  test('[9] the FIRST call of seasons.next returns "summer"', () => {
+    expect(seasons.next()).toBe('summer')
+  })
+  test('[10] the SECOND call of seasons.next returns "fall"', () => {
+    seasons.next()
+    expect(seasons.next()).toBe('fall')
+  })
+  test('[11] the THIRD call of seasons.next returns "winter"', () => {
+    seasons.next()  
+    seasons.next()
+    expect(seasons.next()).toBe('winter')
+  })
+  test('[12] the FOURTH call of seasons.next returns "spring"', () => {
+    seasons.next()
+    seasons.next()
+    seasons.next()
+    expect(seasons.next()).toBe('spring')
+  })
+  test('[13] the FIFTH call of seasons.next returns again "summer"', () => {
+    seasons.next()
+    seasons.next()
+    seasons.next()
+    seasons.next()
+    expect(seasons.next()).toBe('summer')
+  })
+  test('[14] the 40th call of seasons.next returns "spring"', () => {
+    for (let i = 0; i < 39; i++) {
+      seasons.next()
+    }
+    expect(seasons.next()).toBe('spring')
+  })
 })
 
 describe('[Exercise 6] Car', () => {
@@ -48,13 +105,45 @@ describe('[Exercise 6] Car', () => {
   beforeEach(() => {
     focus = new utils.Car('focus', 20, 30) // each test must start with a fresh car
   })
-  // test('[15] driving the car returns the updated odometer', () => {})
-  // test('[16] driving the car uses gas', () => {})
-  // test('[17] refueling allows to keep driving', () => {})
-  // test('[18] adding fuel to a full tank has no effect', () => {})
+  test('[15] driving the car returns the updated odometer', () => {
+    expect(focus.drive(100)).toBe(100)
+    expect(focus.drive(100)).toBe(200)
+    expect(focus.drive(100)).toBe(300)
+    expect(focus.drive(100)).toBe(400)
+    expect(focus.drive(100)).toBe(500)
+    expect(focus.drive(100)).toBe(600)
+    expect(focus.drive(100)).toBe(600) //empty tank
+  })
+  test('[16] driving the car uses gas', () => {
+    focus.drive(600)
+    expect(focus.drive(100)).toBe(600)
+    expect(focus.drive(100)).toBe(600)
+    expect(focus.tank).toBe(0)
+
+  })
+  test('[17] refueling allows to keep driving', () => {
+    focus.drive(600)
+    focus.refuel(10)
+    focus.drive(600)
+    expect(focus.odometer).toBe(900)
+    focus.refuel(20)
+    focus.drive(600)
+    expect(focus.odometer).toBe(1500)
+  })
+  test('[18] adding fuel to a full tank has no effect', () => {
+    focus.refuel(200000)
+    focus.drive(10000)
+    expect(focus.odometer).toBe(600)
+  })
 })
 
 describe('[Exercise 7] isEvenNumberAsync', () => {
-  // test('[19] resolves true if passed an even number', () => {})
-  // test('[20] resolves false if passed an odd number', () => {})
+  test('[19] resolves true if passed an even number', async () => {
+    const result = await utils.isEvenNumberAsync(2)
+    expect(result).toBe(true)
+  })
+  test('[20] resolves false if passed an odd number', async () => {
+    const result = await utils.isEvenNumberAsync(3)
+    expect(result).toBe(false)
+  })
 })