diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index 5c5b796e1..390414624 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -6,9 +6,29 @@
 // or contains values that aren't numbers (the function is expected to throw - see the tests).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (Array.isArray(list) === false) {
+    throw new Error("calculateMedian requires an array of numbers");
+  }
+
+  if (list.length === 0) {
+    throw new Error("calculateMedian requires a non-empty array");
+  }
+
+   if (list.some((item) => typeof item === "string" || item === null || item === undefined)) {
+    throw new Error("calculateMedian requires an array of numbers");
+  }
+
+  const sortedList = [...list].sort((a, b) => a - b);
+
+  if (sortedList.length % 2 === 0) {
+    const evenMiddleIndex = sortedList.length / 2;
+    const sumOfEvenMiddleIndex =
+    sortedList[evenMiddleIndex - 1] + sortedList[evenMiddleIndex]
+    return sumOfEvenMiddleIndex / 2;
+  } else {
+    const oddMiddleIndex = Math.floor(sortedList.length / 2);
+    return sortedList[oddMiddleIndex];
+  }
 }
 
 module.exports = calculateMedian;
diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..7abb5fb70 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,5 @@
-function dedupe() {}
+function dedupe(list) {
+  return [...new Set(list)];
+}
+
+module.exports = dedupe;
diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index d7c8e3d8e..2e226dd99 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -1,28 +1,56 @@
 const dedupe = require("./dedupe.js");
-/*
-Dedupe Array
 
-📖 Dedupe means **deduplicate**
+//Dedupe Array
 
-In this kata, you will need to deduplicate the elements of an array
+//📖 Dedupe means **deduplicate**
 
-E.g. dedupe(['a','a','a','b','b','c']) returns ['a','b','c']
-E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) returns [5, 1, 2, 3, 8]
-E.g. dedupe([1, 2, 1]) returns [1, 2]
-*/
+//In this kata, you will need to deduplicate the elements of an array
 
-// Acceptance Criteria:
+describe("dedupe", () => {
+  //E.g. dedupe(['a','a','a','b','b','c']) returns ['a','b','c']
+  it("returns for ['a','a','a','b','b','c']", () => {
+    expect(dedupe(["a", "a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+  });
 
-// Given an empty array
-// When passed to the dedupe function
-// Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+  //E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) returns [5, 1, 2, 3, 8]
+  it("returns for [5, 1, 1, 2, 3, 2, 5, 8]", () => {
+    expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+  });
+  //E.g. dedupe([1, 2, 1]) returns [1, 2]
+  //*/
+  it("returns for [1, 2, 1]", () => {
+    expect(dedupe([1, 2, 1])).toEqual([1, 2]);
+  });
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
+  // Acceptance Criteria:
 
-// Given an array of strings or numbers
-// When passed to the dedupe function
-// Then it should return a new array with duplicates removed while preserving the 
-// first occurrence of each element from the original array.
+  // Given an empty array
+  // When passed to the dedupe function
+  // Then it should return an empty array
+
+  it("returns for []", () => {
+    expect(dedupe([])).toEqual([]);
+  });
+
+  // Given an array with no duplicates
+  // When passed to the dedupe function
+  // Then it should return a copy of the original array
+
+  it("returns for [1, 2, 3, 4]", () => {
+    const original = [1, 2, 3, 4];
+    const result = dedupe(original);
+    expect(result).not.toBe(original);
+  });
+
+  // Given an array of strings or numbers
+  // When passed to the dedupe function
+  // Then it should return a new array with duplicates removed while preserving the
+  // first occurrence of each element from the original array.
+  it("returns for ['apple', 'orange', 'banana', 'banana']", () => {
+    expect(dedupe(["apple", "orange", "banana", "banana"])).toEqual([
+      "apple",
+      "orange",
+      "banana",
+    ]);
+  });
+});
diff --git a/Sprint-1/implement/describe-median.js b/Sprint-1/implement/describe-median.js
index 3381cfc0a..ea3f8321d 100644
--- a/Sprint-1/implement/describe-median.js
+++ b/Sprint-1/implement/describe-median.js
@@ -1,14 +1,14 @@
 // Don't change this function.
 function calculateMedian(list) {
   if (!Array.isArray(list)) {
-    throw new Error("calculateMedian requires an array of numbers");
+    throw new Error("Could not calculate a median: calculateMedian requires an array of numbers");
   }
   if (list.length === 0) {
-    throw new Error("calculateMedian requires a non-empty array");
+    throw new Error("Could not calculate a median: calculateMedian requires a non-empty array");
   }
   for (const item of list) {
     if (typeof item !== "number") {
-      throw new Error("calculateMedian requires an array of numbers");
+      throw new Error("Could not calculate a median: calculateMedian requires an array of numbers");
     }
   }
   const middleIndex = Math.floor(list.length / 2);
@@ -20,6 +20,9 @@ function calculateMedian(list) {
 }
 
 // Implement this function. See describe-median.test.js for the acceptance criteria.
-function describeMedian(list) {}
+function describeMedian(list) {
+  const result = calculateMedian(list);
+  return `The median is ${result}`
+}
 
 module.exports = describeMedian;
diff --git a/Sprint-1/implement/describe-median.test.js b/Sprint-1/implement/describe-median.test.js
index e7d18a264..59dcf2b57 100644
--- a/Sprint-1/implement/describe-median.test.js
+++ b/Sprint-1/implement/describe-median.test.js
@@ -21,12 +21,32 @@ const describeMedian = require("./describe-median.js");
 // When passed to describeMedian
 // Then it should return "The median is " followed by the median
 // Delete this test.todo and replace it with a test.
-test.todo('given [1, 2, 3], returns "The median is 2"');
-
-// Given an empty array
-// When passed to describeMedian
-// Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
-
-// Given something that isn't an array of numbers, e.g. "banana"
-// When passed to describeMedian
-// Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"
+describe("describeMedian", () => {
+  it("returns for [1, 2, 3, 4]", () => {
+    const array = [1, 2, 3, 4];
+    const result = describeMedian(array);
+    expect(result).toBe("The median is 2.5");
+  });
+
+  // Given an empty array
+  // When passed to describeMedian
+  // Then it should return "Could not calculate a median: calculateMedian requires a non-empty array"
+  it("returns for []", () => {
+    expect(() => describeMedian([])).toThrow(
+      new Error(
+        "Could not calculate a median: calculateMedian requires a non-empty array"
+      )
+    );
+  });
+
+  // Given something that isn't an array of numbers, e.g. "banana"
+  // When passed to describeMedian
+  // Then it should return "Could not calculate a median: calculateMedian requires an array of numbers"
+  it("returns for ['banana', 'apple', 'orange']", () => {
+    expect(() => describeMedian(["banana", "apple", "orange"])).toThrow(
+      new Error(
+        "Could not calculate a median: calculateMedian requires an array of numbers"
+      )
+    );
+  });
+});
diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..05562c338 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,10 @@
 function findMax(elements) {
+  if (!Array.isArray(elements)) {
+    throw new Error("findMax requires an array of numbers");
+  }
+  if (elements.some((element) => typeof element === "string")) {
+    throw new Error("findMax requires an array of numbers");
+  }
+  return Math.max(...elements);
 }
-
 module.exports = findMax;
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index ff3fbb5e5..0623badf0 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -16,28 +16,72 @@ const findMax = require("./max.js");
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+describe("findMax", () => {
+  it("returns for []", () => {
+    expect(findMax([])).toEqual(-Infinity);
+  });
 
-// Given an array with one number
-// When passed to the max function
-// Then it should return that number
+  // Given an array with one number
+  // When passed to the max function
+  // Then it should return that number
+  it("returns for [17]", () => {
+    expect(findMax([17])).toEqual(17);
+  });
 
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
+  // Given an array with both positive and negative numbers
+  // When passed to the max function
+  // Then it should return the largest number overall
 
-// Given an array with just negative numbers
-// When passed to the max function
-// Then it should return the closest one to zero
+  it("returns for [-6, 15, 30, 42, -90]", () => {
+    expect(findMax([-6, 15, 30, 42, -90])).toEqual(42);
+  });
 
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
+  // Given an array with just negative numbers
+  // When passed to the max function
+  // Then it should return the closest one to zero
 
-// Given an array containing a value that isn't a number
-// When passed to the max function
-// Then it should throw Error("findMax requires an array of numbers")
+  it("returns for [-6, 15, 30, 42, -90]", () => {
+    expect(findMax([-6, 15, 30, 42, -90])).toEqual(42);
+  });
 
-// Given something that isn't an array at all, such as "hey", 42 or no argument
-// When passed to the max function
-// Then it should throw Error("findMax requires an array of numbers")
+  // Given an array with decimal numbers
+  // When passed to the max function
+  // Then it should return the largest decimal number
+
+  it("returns for [0.5, 1.5, 3.5, 5.5, 7.5]", () => {
+    expect(findMax([0.5, 1.5, 3.5, 5.5, 7.5])).toEqual(7.5);
+  });
+
+  // Given an array containing a value that isn't a number
+  // When passed to the max function
+  // Then it should throw Error("findMax requires an array of numbers")
+
+  it("returns for [2, 4, 'hello', 6, 8, 10]", () => {
+    () =>
+      expect(findMax([2, 4, "hello", 6, 8, 10])).toThrow(
+        new Error("findMax requires an array of numbers")
+      );
+  });
+
+  // Given something that isn't an array at all, such as "hey", 42 or no argument
+  // When passed to the max function
+  // Then it should throw Error("findMax requires an array of numbers")
+
+  it("returns for 'hey'", () => {
+    expect(() => findMax("hey")).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+  });
+
+  it("returns for 42", () => {
+    expect(() => findMax(42)).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+  });
+
+  it("returns for ''", () => {
+    expect(() => findMax()).toThrow(
+      new Error("findMax requires an array of numbers")
+    );
+  });
+});
diff --git a/Sprint-1/implement/mean.js b/Sprint-1/implement/mean.js
index 36909ea1f..0e984b9ef 100644
--- a/Sprint-1/implement/mean.js
+++ b/Sprint-1/implement/mean.js
@@ -1,3 +1,24 @@
-function calculateMean(list) {}
+function calculateMean(list) {
+  if (!Array.isArray(list)) {
+    throw new Error("calculateMean requires an array of numbers");
+  }
+
+  if (list.length === 0) {
+    throw new Error("calculateMean requires a non-empty array");
+  }
+
+  if (list.some((item) => typeof item === "string")) {
+    throw new Error("calculateMean requires an array of numbers");
+  }
+
+  let sum = 0;
+  for (const item of list) {
+    sum += item;
+  }
+
+  const mean = sum / list.length;
+
+  return mean;
+}
 
 module.exports = calculateMean;
diff --git a/Sprint-1/implement/mean.test.js b/Sprint-1/implement/mean.test.js
index 847b88676..06f572107 100644
--- a/Sprint-1/implement/mean.test.js
+++ b/Sprint-1/implement/mean.test.js
@@ -23,28 +23,91 @@ const calculateMean = require("./mean.js");
 // When passed to calculateMean
 // Then it should return their mean
 // Delete this test.todo and replace it with a test.
-test.todo("given [1, 2, 6], returns 3");
+describe("calculateMean", () => {
+  it("return [1, 2, 6]", () => {
+    expect(calculateMean([1, 2, 6])).toEqual(3);
+  });
 
-// Given an array with a single number
-// When passed to calculateMean
-// Then it should return that number
+  // Given an array with a single number
+  // When passed to calculateMean
+  // Then it should return that number
+  it("returns for [6]", () => {
+    expect(calculateMean([6])).toEqual(6);
+  });
 
-// Given an array containing negative or decimal numbers
-// When passed to calculateMean
-// Then it should return the correct mean
+  // Given an array containing negative or decimal numbers
+  // When passed to calculateMean
+  // Then it should return the correct mean
+  it("returns for 10, 20.5, -10, 30.5]", () => {
+    expect(calculateMean([10, 20.5, -10, 30.5])).toEqual(12.75);
+  });
 
-// Given an empty array
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires a non-empty array")
+  it ("returns for [1.2, 0.6, 0.005]", () => {
+    expect(calculateMean([1.2, 0.6, 0.005])).toBeCloseTo(0.6017);
 
-// Given a value that isn't an array, e.g. "banana", 42, null or {}
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+  });
 
-// Given no argument at all
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+  // Given an empty array
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires a non-empty array")
 
-// Given an array containing a non-number value, e.g. [1, "2", 3]
-// When passed to calculateMean
-// Then it should throw Error("calculateMean requires an array of numbers")
+  it("returns for []", () => {
+    () =>
+      expect(calculateMean([])).toThrow(
+        new Error("calculateMean requires a non-empty array")
+      );
+  });
+
+  // Given a value that isn't an array, e.g. "banana", 42, null or {}
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires an array of numbers")
+
+  it("returns for 'banana'", () => {
+    () =>
+      expect(calculateMean("banana")).toThrow(
+        new Error("calculateMean requires an array of numbers")
+      );
+  });
+
+  it("returns for 42", () => {
+    () =>
+      expect(calculateMean(42)).toThrow(
+        new Error("calculateMean requires an array of numbers")
+      );
+  });
+
+  it("returns for null", () => {
+    () =>
+      expect(calculateMean(null)).toThrow(
+        new Error("calculateMean requires an array of numbers")
+      );
+  });
+
+  it("returns for {}", () => {
+    () =>
+      expect(calculateMean({})).toThrow(
+        new Error("calculateMean requires an array of numbers")
+      );
+  });
+
+  // Given no argument at all
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires an array of numbers")
+
+  it("returns for ''", () => {
+    () =>
+      expect(calculateMean("")).toThrow(
+        new Error("calculateMean requires an array of numbers")
+      );
+  });
+
+  // Given an array containing a non-number value, e.g. [1, "2", 3]
+  // When passed to calculateMean
+  // Then it should throw Error("calculateMean requires an array of numbers")
+  it("returns for [1, '2', 3]", () => {
+    () =>
+      expect(calculateMean([1, "2", 3])).toThrow(
+        new Error("calculateMean requires an array of numbers")
+      );
+  });
+});
diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..03c5718dc 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,17 @@
 function sum(elements) {
+  if (!Array.isArray(elements) || elements === "") {
+    throw new Error("sum requires an array of numbers");
+  }
+
+  if (elements.some((element) => typeof element === "string")) {
+    throw new Error("sum requires an array of numbers");
+  }
+  let result = 0;
+  for (const element of elements) {
+    result += element;
+  }
+
+  return result;
 }
 
 module.exports = sum;
diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index a288e0f0a..3298d4896 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -13,24 +13,57 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+describe("sum", () => {
+  it("returns for []", () => {
+    expect(sum([])).toEqual(0);
+  });
+  // Given an array with just one number
+  // When passed to the sum function
+  // Then it should return that number
+  it("returns for [8]", () => {
+    expect(sum([8])).toEqual(8);
+  });
+  // Given an array containing negative numbers
+  // When passed to the sum function
+  // Then it should still return the correct total sum
+  it("returns for [8, -5, 10]", () => {
+    expect(sum([8, -5, 10])).toEqual(13);
+  });
 
-// Given an array with just one number
-// When passed to the sum function
-// Then it should return that number
+  // Given an array with decimal/float numbers
+  // When passed to the sum function
+  // Then it should return the correct total sum
+  it("returns for [10, 3.75, 2.25]", () => {
+    expect(sum([10, 3.75, 2.25])).toEqual(16);
+  });
+  // Given an array containing a value that isn't a number
+  // When passed to the sum function
+  // Then it should throw Error("sum requires an array of numbers")
 
-// Given an array containing negative numbers
-// When passed to the sum function
-// Then it should still return the correct total sum
+  it("returns for [10, 20, '30']", () => {
+    () =>
+      expect(
+        sum([10, 20, "30"]).toThrow(
+          new Error("sum requires an array of numbers")
+        )
+      );
+  });
 
-// Given an array with decimal/float numbers
-// When passed to the sum function
-// Then it should return the correct total sum
+  // Given something that isn't an array at all, such as "hey", 42 or no argument
+  // When passed to the sum function
+  // Then it should throw Error("sum requires an array of numbers")
+  it("returns for 'hey'", () => {
+    () =>
+      expect(sum("hey")).toThrow(new Error("sum requires an array of numbers"));
+  });
 
-// Given an array containing a value that isn't a number
-// When passed to the sum function
-// Then it should throw Error("sum requires an array of numbers")
+  it("returns for (42)", () => {
+    () =>
+      expect(sum(42)).toThrow(new Error("sum requires an array of numbers"));
+  });
 
-// Given something that isn't an array at all, such as "hey", 42 or no argument
-// When passed to the sum function
-// Then it should throw Error("sum requires an array of numbers")
+  it("returns for ('')", () => {
+    () =>
+      expect(sum("")).toThrow(new Error("sum requires an array of numbers"));
+  });
+});
diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 29dad81f0..6aeac0b5d 100644
--- a/Sprint-1/refactor/includes.js
+++ b/Sprint-1/refactor/includes.js
@@ -1,9 +1,8 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
-    if (element === target) {
+  for (const item of list) {
+    if (item === target) {
       return true;
     }
   }