diff --git a/index.js b/index.js
index 28090f12..ce11f6d4 100644
--- a/index.js
+++ b/index.js
@@ -1,3 +1,4 @@
+
 /**
  * [Exercise 1] trimProperties copies an object trimming its properties
  * @param {object} obj - an object with properties that are strings
@@ -7,7 +8,11 @@
  * trimProperties({ name: '  jane  ' }) // returns a new object { name: 'jane' }
  */
 function trimProperties(obj) {
-  // ✨ implement
+  let trimmedObj = {};
+  for (const prop in obj) {
+    trimmedObj = {...trimmedObj, [prop]: obj[prop].trim()};
+  }
+  return trimmedObj;
 }
 
 /**
@@ -19,7 +24,10 @@ function trimProperties(obj) {
  * trimPropertiesMutation({ name: '  jane  ' }) // returns the object mutated in place { name: 'jane' }
  */
 function trimPropertiesMutation(obj) {
-  // ✨ implement
+  for (const prop in obj) {
+    obj[prop] = obj[prop].trim();
+  }
+  return obj;
 }
 
 /**
@@ -31,7 +39,11 @@ function trimPropertiesMutation(obj) {
  * findLargestInteger([{ integer: 1 }, { integer: 3 }, { integer: 2 }]) // returns 3
  */
 function findLargestInteger(integers) {
-  // ✨ implement
+  const intArr = [];
+  integers.forEach(obj => {
+    intArr.push(obj.integer);
+  });
+  return Math.max(...intArr);
 }
 
 class Counter {
@@ -40,7 +52,8 @@ class Counter {
    * @param {number} initialNumber - the initial state of the count
    */
   constructor(initialNumber) {
-    // ✨ initialize whatever properties are needed
+    this.initialNumber = initialNumber;
+    this.countDownCount = 0;
   }
 
   /**
@@ -56,7 +69,16 @@ class Counter {
    * counter.countDown() // returns 0
    */
   countDown() {
-    // ✨ implement
+    this.countDownCount++;
+    if (this.countDownCount === 1) {
+      return this.initialNumber;
+    } else {
+      if (this.initialNumber - (this.countDownCount -1) <= 0) {
+        return 0;
+      } else {
+        return this.initialNumber - (this.countDownCount - 1);
+      }
+    }
   }
 }
 
@@ -65,7 +87,8 @@ class Seasons {
    * [Exercise 5A] Seasons creates a seasons object
    */
   constructor() {
-    // ✨ initialize whatever properties are needed
+    this.seasons = ["summer", "fall", "winter", "spring"];
+    this.count = -1;
   }
 
   /**
@@ -81,7 +104,8 @@ class Seasons {
    * seasons.next() // returns "summer"
    */
   next() {
-    // ✨ implement
+    this.count++;
+    return this.seasons[this.count % 4];
   }
 }
 
@@ -93,9 +117,11 @@ class Car {
    * @param {number} mpg - miles the car can drive per gallon of gas
    */
   constructor(name, tankSize, mpg) {
-    this.odometer = 0 // car initilizes with zero miles
-    this.tank = tankSize // car initiazes full of gas
-    // ✨ initialize whatever other properties are needed
+    this.car = name;
+    this.odometer = 0; // car initilizes with zero miles
+    this.tank = tankSize; // car initiazes full of gas
+    this.fuel = tankSize;
+    this.mpg = mpg;
   }
 
   /**
@@ -112,7 +138,13 @@ class Car {
    * focus.drive(200) // returns 600 (ran out of gas after 100 miles)
    */
   drive(distance) {
-    // ✨ implement
+    let fuelUsed = distance / this.mpg;
+    if (this.fuel - fuelUsed <= 0){
+      fuelUsed = fuelUsed + (this.fuel - fuelUsed); 
+    }
+    this.fuel -= fuelUsed;
+    this.odometer += Math.round(fuelUsed * this.mpg);
+    return this.odometer;
   }
 
   /**
@@ -127,7 +159,11 @@ class Car {
    * focus.refuel(99) // returns 600 (tank only holds 20)
    */
   refuel(gallons) {
-    // ✨ implement
+    if (gallons >= this.tank) {
+      this.fuel = this.tank;
+    } else {
+      this.fuel = gallons;
+    }
   }
 }
 
@@ -151,7 +187,15 @@ class Car {
  * })
  */
 function isEvenNumberAsync(number) {
-  // ✨ implement
+  if (!number || typeof number !== "number") {
+    return Promise.reject('number must be a number');
+  } else {
+    if (number % 2 === 0) {
+      return Promise.resolve(true);
+    } else {
+      return Promise.resolve(false);
+    }
+  }
 }
 
 module.exports = {
@@ -162,4 +206,4 @@ module.exports = {
   Counter,
   Seasons,
   Car,
-}
+};
\ No newline at end of file
diff --git a/index.test.js b/index.test.js
index b9d30ded..3a65623b 100644
--- a/index.test.js
+++ b/index.test.js
@@ -1,62 +1,183 @@
-const utils = require('./index')
+const utils = require('./index');
 
 describe('[Exercise 1] trimProperties', () => {
   test('[1] 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.todo('[2] returns a copy, leaving the original object intact')
-})
+    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('[2] returns a copy, leaving the original object intact' , () => {
+    const input = { foo: 'foo  ', bar: ' bar ', baz: '  baz' };
+    utils.trimProperties(input);
+    const output = { foo: 'foo', bar: 'bar', baz: 'baz' };
+    expect(input).not.toEqual(output);
+  });
+});
 
 describe('[Exercise 2] trimPropertiesMutation', () => {
-  test.todo('[3] returns an object with the properties trimmed')
-  test.todo('[4] the object returned is the exact same one we passed in')
-})
+  test('[3] returns an object with the properties trimmed', () => {
+    const input = { foo: '  foo ', bar: 'bar ', baz: ' baz' };
+    const expected = { foo: 'foo', bar: 'bar', baz: 'baz' };
+    const actual = utils.trimPropertiesMutation(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' };
+    utils.trimPropertiesMutation(input);
+    const output = { foo: 'foo', bar: 'bar', baz: 'baz' };
+    expect(input).toEqual(output);
+  });
+});
 
 describe('[Exercise 3] findLargestInteger', () => {
-  test.todo('[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 }', () => {
+    const integers = [
+      {integer: 1},
+      {integer: 2},
+      {integer: 5}
+    ];
+    const largest = utils.findLargestInteger(integers);
+    expect(largest).toBe(5);
+  });
+
+  test('[5a] returns the largest number in an array of objects { integer: 2 }', () => {
+    const integers = [
+      {integer: 4},
+      {integer: 2},
+      {integer: 5},
+      {integer: 5},
+      {integer: 17},
+      {integer: 17},
+    ];
+    const largest = utils.findLargestInteger(integers);
+    expect(largest).toBe(17);
+  });
+});
 
 describe('[Exercise 4] Counter', () => {
-  let counter
+  let counter;
   beforeEach(() => {
-    counter = new utils.Counter(3) // each test must start with a fresh couter
-  })
-  test.todo('[6] the FIRST CALL of counter.countDown returns the initial count')
-  test.todo('[7] the SECOND CALL of counter.countDown returns the initial count minus one')
-  test.todo('[8] the count eventually reaches zero but does not go below zero')
-})
+    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', () => {
+    const count = counter.countDown();
+    expect(count).toBe(3);
+  });
+  test('[7] the SECOND CALL of counter.countDown returns the initial count minus one', () => {
+    counter.countDown();
+    const count = counter.countDown();
+    expect(count).toBe(2);
+  });
+  test('[8] the count eventually reaches zero but does not go below zero', () => {
+    counter.countDown();
+    counter.countDown();
+    counter.countDown();
+    counter.countDown();
+    counter.countDown();
+    const count = counter.countDown();
+    expect(count).toBe(0);
+  });
+});
 
 describe('[Exercise 5] Seasons', () => {
-  let seasons
+  let seasons;
   beforeEach(() => {
-    seasons = new utils.Seasons() // each test must start with fresh seasons
-  })
-  test.todo('[9] the FIRST call of seasons.next returns "summer"')
-  test.todo('[10] the SECOND call of seasons.next returns "fall"')
-  test.todo('[11] the THIRD call of seasons.next returns "winter"')
-  test.todo('[12] the FOURTH call of seasons.next returns "spring"')
-  test.todo('[13] the FIFTH call of seasons.next returns again "summer"')
-  test.todo('[14] the 40th call of seasons.next returns "spring"')
-})
+    seasons = new utils.Seasons(); // each test must start with fresh seasons
+  });
+  test('[9] the FIRST call of seasons.next returns "summer"', () => {
+    const season = seasons.next();
+    expect(season).toBe("summer");
+  });
+  test('[10] the SECOND call of seasons.next returns "fall"', () => {
+    seasons.next();
+    const season = seasons.next();
+    expect(season).toBe("fall");
+  });
+  test('[11] the THIRD call of seasons.next returns "winter"', () => {
+    let season;
+    for (let i = 0; i<3; i++) {
+      season = seasons.next();
+    }
+    expect(season).toBe("winter");
+  });
+  test('[12] the FOURTH call of seasons.next returns "spring"', () => {
+    let season;
+    for (let i = 0; i<4; i++) {
+      season = seasons.next();
+    }
+    expect(season).toBe("spring");
+  });
+  test('[13] the FIFTH call of seasons.next returns again "summer"', () => {
+    let season;
+    for (let i = 0; i<5; i++) {
+      season = seasons.next();
+    }
+    expect(season).toBe("summer");
+  });
+  test('[14] the 40th call of seasons.next returns "spring"', () => {
+    let season;
+    for (let i = 0; i<40; i++) {
+      season = seasons.next();
+    }
+    expect(season).toBe("spring");
+  });
+});
 
 describe('[Exercise 6] Car', () => {
-  let focus
+  let focus;
   beforeEach(() => {
-    focus = new utils.Car('focus', 20, 30) // each test must start with a fresh car
-  })
-  test.todo('[15] driving the car returns the updated odometer')
-  test.todo('[16] driving the car uses gas')
-  test.todo('[17] refueling allows to keep driving')
-  test.todo('[18] adding fuel to a full tank has no effect')
-})
+    focus = new utils.Car('focus', 20, 30); // each test must start with a fresh car
+  });
+  test('[15] driving the car returns the updated odometer', () => {
+    focus.drive(10);
+    expect(focus.odometer).toBe(10);
+  });
+  test('[16] driving the car uses gas', () => {
+    focus.drive(30);
+    const gasLeft = 19; //30 miles at 30 mpg uses 1 gallon. Tank holds 20;
+    expect(focus.fuel).toBe(gasLeft);
+  });
+  test('[17] refueling allows to keep driving', () => {
+    focus.drive(610); //run out of gas
+    expect(focus.odometer).toBe(600); //600 max miles on tank
+    focus.drive(1);
+    expect(focus.odometer).toBe(600);
+    focus.refuel(100); //fills tank
+    focus.drive(610); //full tank only goes 600 miles.
+    expect(focus.odometer).toBe(1200);
+  });
+  test('[18] adding fuel to a full tank has no effect', () => {
+    focus.refuel(200);
+    expect(focus.fuel).toBe(20); //20 is tank size;
+  });
+});
 
 describe('[Exercise 7] isEvenNumberAsync', () => {
-  test.todo('[19] resolves true if passed an even number')
-  test.todo('[20] resolves false if passed an odd number')
-  test.todo('[21] rejects an error with the message "number must be a number" if passed a non-number type')
-  test.todo('[22] rejects an error with the message "number must be a number" if passed NaN')
-})
+  test('[19] resolves true if passed an even number', async () => {
+    const evenNumber = 4;
+    const result = await utils.isEvenNumberAsync(evenNumber);
+    expect(result).toBe(true);
+  });
+  test('[20] resolves false if passed an odd number', async () => {
+    const oddNumber = 5;
+    const result = await utils.isEvenNumberAsync(oddNumber);
+    expect(result).toBe(false);
+  });
+  test('[21] rejects an error with the message "number must be a number" if passed a non-number type', () => {
+    const string = "5";
+    utils.isEvenNumberAsync(string)
+      .then()
+      .catch(err => {
+        expect(err).toBe("number must be a number");
+      });
+  });
+  test('[22] rejects an error with the message "number must be a number" if passed NaN', () => {
+    utils.isEvenNumberAsync(NaN)
+      .then()
+      .catch(err => {
+        expect(err).toBe("number must be a number");
+      });
+  });
+});
\ No newline at end of file