diff --git a/index.js b/index.js
index 3df06ec1..6b14a783 100644
--- a/index.js
+++ b/index.js
@@ -8,6 +8,12 @@
  */
 function trimProperties(obj) {
   // ✨ implement
+  const result = {};
+  for (let prop in obj) {
+    result[prop] = obj[prop].trim();
+  }
+  // console.log(result);
+  return result;
 }
 
 /**
@@ -20,6 +26,10 @@ function trimProperties(obj) {
  */
 function trimPropertiesMutation(obj) {
   // ✨ implement
+  for (let prop in obj) {
+    obj[prop] = obj[prop].trim();
+  }
+  return obj;
 }
 
 /**
@@ -31,7 +41,13 @@ function trimPropertiesMutation(obj) {
  * findLargestInteger([{ integer: 1 }, { integer: 3 }, { integer: 2 }]) // returns 3
  */
 function findLargestInteger(integers) {
-  // ✨ implement
+  let result = integers[0].integer;
+  for (let idx = 0; idx < integers.length; idx++) {
+    if (integers[idx].integer > result) {
+      result = integers[idx].integer;
+    }
+  }
+  return result;
 }
 
 class Counter {
@@ -41,6 +57,7 @@ class Counter {
    */
   constructor(initialNumber) {
     // ✨ initialize whatever properties are needed
+    this.count = initialNumber;
   }
 
   /**
@@ -56,7 +73,12 @@ class Counter {
    * counter.countDown() // returns 0
    */
   countDown() {
-    // ✨ implement
+    return this.count > 0 ? this.count-- : 0;
+    // or:
+    // if (this.count > 0) {
+    //   return this.count--;
+    // }
+    // return this.count;
   }
 }
 
@@ -66,6 +88,8 @@ class Seasons {
    */
   constructor() {
     // ✨ initialize whatever properties are needed
+    this.seasons = ["summer", "fall", "winter", "spring"];
+    this.currentSeason = 0;
   }
 
   /**
@@ -82,6 +106,13 @@ class Seasons {
    */
   next() {
     // ✨ implement
+    const result = this.seasons[this.currentSeason];
+    if (this.currentSeason === 3) {
+      this.currentSeason = 0;
+    } else {
+      ++this.currentSeason;
+    }
+    return result;
   }
 }
 
@@ -93,9 +124,11 @@ 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
+    this.odometer = 0; // car initilizes with zero miles
+    this.tank = tankSize; // car initiazes full of gas
     // ✨ initialize whatever other properties are needed
+    this.tankSize = tankSize;
+    this.mpg = mpg;
   }
 
   /**
@@ -113,6 +146,15 @@ class Car {
    */
   drive(distance) {
     // ✨ implement
+    const milesCanDrive = this.tank * this.mpg;
+    if (distance <= milesCanDrive) {
+      this.odometer = this.odometer + distance;
+      this.tank = this.tank - distance / this.mpg;
+    } else {
+      this.tank = 0;
+      this.odometer = this.odometer + milesCanDrive;
+    }
+    return this.odometer;
   }
 
   /**
@@ -128,6 +170,12 @@ class Car {
    */
   refuel(gallons) {
     // ✨ implement
+    if (gallons <= this.tankSize - this.tank) {
+      this.tank = this.tank + gallons;
+    } else {
+      this.tank = this.tankSize;
+    }
+    return this.tank * this.mpg;
   }
 }
 
@@ -137,15 +185,22 @@ class Car {
  * @returns {promise} - resolves true if number even, false otherwise
  *
  * EXAMPLE
- * isEvenNumberAsync(2).then(result => {
- *    // result is true
  * })
  * isEvenNumberAsync(3).then(result => {
  *    // result is false
  * })
  */
-function isEvenNumberAsync(number) {
-  // ✨ implement
+async function isEvenNumberAsync(number) {
+  if (typeof number !== "number" || isNaN(number)) {
+    throw new Error("error");
+  }
+  return number % 2 === 0 || false;
+  // ✨ or:
+  // if (number % 2 === 0) {
+  //   return true;
+  // } else {
+  // return false;
+  // }
 }
 
 module.exports = {
@@ -156,4 +211,4 @@ module.exports = {
   Counter,
   Seasons,
   Car,
-}
+};
diff --git a/index.test.js b/index.test.js
index cfb0a0b3..cc44e724 100644
--- a/index.test.js
+++ b/index.test.js
@@ -1,60 +1,168 @@
-const utils = require('./index')
+const utils = require("./index");
 
-describe('[Exercise 1] trimProperties', () => {
-  test('[1] returns an object with the properties trimmed', () => {
+test("this test works great", () => {
+  //empty test
+});
+
+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('[2] returns a copy, leaving the original object intact', () => {})
-})
-
-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', () => {})
-})
-
-describe('[Exercise 3] findLargestInteger', () => {
-  // test('[5] returns the largest number in an array of objects { integer: 2 }', () => {})
-})
-
-describe('[Exercise 4] Counter', () => {
-  let counter
+    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);
+    expect(input).toEqual({ foo: "  foo ", bar: "bar ", baz: " baz" });
+  });
+});
+
+describe("[Exercise 2] trimPropertiesMutation", () => {
+  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.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 }", () => {
+    const input = [{ integer: 1 }, { integer: 3 }, { integer: 2 }];
+    const input2 = [{ integer: 4 }, { integer: 3 }, { integer: 2 }];
+    const input3 = [{ integer: 1 }, { integer: 3 }, { integer: 4 }];
+    const actual = utils.findLargestInteger(input);
+    const actual2 = utils.findLargestInteger(input2);
+    const actual3 = utils.findLargestInteger(input3);
+    expect(actual).toBe(3);
+    expect(actual2).toBe(4);
+    expect(actual3).toBe(4);
+  });
+});
+
+describe("[Exercise 4] Counter", () => {
+  let 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', () => {})
-})
-
-describe('[Exercise 5] Seasons', () => {
-  let seasons
+    counter = new utils.Counter(3); // each test must start with a fresh counter
+  });
+  test("[6] the FIRST CALL of counter.countDown returns the initial count", () => {
+    expect(counter.countDown()).toBe(3);
+  });
+  test("[7] the SECOND CALL of counter.countDown returns the initial count minus one", () => {
+    counter.countDown();
+    expect(counter.countDown()).toBe(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()).toBe(0);
+  });
+});
+
+describe("[Exercise 5] Seasons", () => {
+  let 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"', () => {})
-})
-
-describe('[Exercise 6] Car', () => {
-  let focus
+    seasons = new utils.Seasons(); // each test must start with fresh seasons
+  });
+  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", () => {
+  let focus;
   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', () => {})
-})
-
-describe('[Exercise 7] isEvenNumberAsync', () => {
-  // test('[19] resolves true if passed an even number', () => {})
-  // test('[20] resolves false if passed an odd number', () => {})
-})
+    focus = new utils.Car("focus", 20, 30); // each test must start with a fresh car
+  });
+  test("[B] has an odometer initialized at zero", () => {
+    expect(focus.odometer).toBe(0);
+  });
+  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(200)).toBe(500);
+    // expect(focus.drive(200)).toBe(600);
+  });
+
+  test("[16] driving the car uses gas", () => {
+    focus.drive(600);
+    expect(focus.drive(1)).toBe(600);
+    expect(focus.drive(1)).toBe(600);
+    expect(focus.drive(1)).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(20000000);
+    focus.drive(100000);
+    expect(focus.odometer).toBe(600);
+  });
+});
+
+describe("[Exercise 7] isEvenNumberAsync", () => {
+  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);
+  });
+
+  test("[21] rejects an error - NOT ON TEST", async () => {
+    try {
+      await utils.isEvenNumberAsync("isNaN");
+    } catch (error) {
+      expect(error.message).toMatch(/error/i);
+    }
+  });
+});
diff --git a/jest.config.js b/jest.config.js
index b150ac59..dab50f78 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -11,7 +11,7 @@ module.exports = {
   // bail: 0,
 
   // The directory where Jest should store its cached dependency information
-  // cacheDirectory: "/private/var/folders/78/wsw4bc497l1b0dlb3f77xh380000gn/T/jest_dx",
+  // cacheDirectory: "/private/var/folders/4q/91xyqb651fz9_4dwn3l5flyr0000gn/T/jest_dx",
 
   // Automatically clear mock calls and instances between every test
   // clearMocks: false,