diff --git a/practice-tdd/count.js b/practice-tdd/count.js
index 5518c5712..ed59a8e24 100644
--- a/practice-tdd/count.js
+++ b/practice-tdd/count.js
@@ -1,3 +1,10 @@
 export function countChar(stringOfCharacters, findCharacter) {
-  return 5
+  let count = 0;
+
+  for (let i = 0; i < stringOfCharacters.length; i++) {
+    if (stringOfCharacters[0] === findCharacter) {
+      count = count + 1;
+    }
+  }
+  return count;
 }
diff --git a/practice-tdd/count.test.js b/practice-tdd/count.test.js
index cb3aaae59..3adafeb41 100644
--- a/practice-tdd/count.test.js
+++ b/practice-tdd/count.test.js
@@ -1,4 +1,6 @@
 // implement a function countChar that counts the number of times a character occurs in a string
+import { test } from "node:test";
+import { strict as assert } from "node:assert";
 import { countChar } from "./count.js";
 // Given a string `str` and a single character `char` to search for,
 // When the countChar function is called with these inputs,
@@ -14,7 +16,7 @@ test("should count multiple occurrences of a character", () => {
   const str = "aaaaa";
   const char = "a";
   const count = countChar(str, char);
-  expect(count).toEqual(5);
+  assert.equal(count, 5);
 });
 
 // Scenario: No Occurrences
@@ -22,3 +24,17 @@ test("should count multiple occurrences of a character", () => {
 // And a character `char` that does not exist within `str`.
 // When the function is called with these inputs,
 // Then it should return 0, indicating that no occurrences of `char` were found.
+
+test("should return 0 when there are no occurrences of a character", () => {
+  const str = "hello";
+  const char = "z";
+  const count = countChar(str, char);
+  assert.equal(count, 0);
+});
+
+test("should return 0 when the string is empty", () => {
+  const str = "";
+  const char = "a";
+  const count = countChar(str, char);
+  assert.equal(count, 0);
+});
diff --git a/practice-tdd/get-ordinal-number.js b/practice-tdd/get-ordinal-number.js
index 5c6291f5e..05df2fea4 100644
--- a/practice-tdd/get-ordinal-number.js
+++ b/practice-tdd/get-ordinal-number.js
@@ -1,3 +1,25 @@
 export function getOrdinalNumber(num) {
-  return "1st";
+  if (num % 100 === 11) {
+    return `${num}th`;
+  }
+  if (num % 100 === 12) {
+    return `${num}th`;
+  }
+
+  if (num % 100 === 13) {
+    return `${num}th`;
+  }
+
+  if (num % 10 === 1) {
+    return `${num}st`;
+  }
+
+  if (num % 10 === 2) {
+    return `${num}nd`;
+  }
+
+  if (num % 10 === 3) {
+    return `${num}rd`;
+  }
+  return `${num}th`;
 }
diff --git a/practice-tdd/get-ordinal-number.test.js b/practice-tdd/get-ordinal-number.test.js
index e23174a18..c1cfc8721 100644
--- a/practice-tdd/get-ordinal-number.test.js
+++ b/practice-tdd/get-ordinal-number.test.js
@@ -1,3 +1,5 @@
+import { test } from "node:test";
+import { strict as assert } from "node:assert";
 import { getOrdinalNumber } from "./get-ordinal-number.js";
 // In this week's prep, we started implementing getOrdinalNumber.
 
@@ -14,7 +16,52 @@ import { getOrdinalNumber } from "./get-ordinal-number.js";
 // When the number ends with 1, except those ending with 11,
 // Then the function should return a string by appending "st" to the number.
 test("should append 'st' for numbers ending with 1, except those ending with 11", () => {
-  expect(getOrdinalNumber(1)).toEqual("1st");
-  expect(getOrdinalNumber(21)).toEqual("21st");
-  expect(getOrdinalNumber(131)).toEqual("131st");
+  assert.equal(getOrdinalNumber(1), "1st");
+  assert.equal(getOrdinalNumber(21), "21st");
+  assert.equal(getOrdinalNumber(131), "131st");
+});
+
+//Test that numbers ending in 11 use "th".
+test("should return 'th' for the numbers ending in 11", () => {
+  assert.equal(getOrdinalNumber(11), "11th");
+});
+
+//Test that numbers ending in 2, excluding numbers ending in 12.
+test("should append 'nd' for the numbers ending in 2, except those ending in 12", () => {
+  assert.equal(getOrdinalNumber(2), "2nd");
+  assert.equal(getOrdinalNumber(22), "22nd");
+  assert.equal(getOrdinalNumber(132), "132nd");
+});
+
+//Test that numbers ending in 3, excluding numbers ending in 13.
+test("should append 'rd' for the numbers ending in 3, except those ending in 13", () => {
+  assert.equal(getOrdinalNumber(3), "3rd");
+  assert.equal(getOrdinalNumber(33), "33rd");
+  assert.equal(getOrdinalNumber(133), "133rd");
+});
+
+//Test that numbers ending in 13 use "th".
+test("should return 'th' for the numbers ending in 13", () => {
+  assert.equal(getOrdinalNumber(13), "13th");
+  assert.equal(getOrdinalNumber(113), "113th");
+});
+
+//Test that numbers not ending in 1, 2, or 3 use "th".
+test("should append 'th' for other numbers", () => {
+  assert.equal(getOrdinalNumber(4), "4th");
+  assert.equal(getOrdinalNumber(7), "7th");
+  assert.equal(getOrdinalNumber(10), "10th");
+  assert.equal(getOrdinalNumber(20), "20th");
+});
+
+//Test that larger numbers ending in 12 use "th".
+test("should return 'th' for the numbers ending in 12", () => {
+  assert.equal(getOrdinalNumber(12), "12th");
+  assert.equal(getOrdinalNumber(112), "112th");
+});
+
+//Test that larger numbers ending in 11 use "th".
+test("should return 'th' for the numbers ending in 11", () => {
+  assert.equal(getOrdinalNumber(11), "11th");
+  assert.equal(getOrdinalNumber(111), "111th");
 });
diff --git a/practice-tdd/repeat-str.js b/practice-tdd/repeat-str.js
index af273f3b0..56da71b83 100644
--- a/practice-tdd/repeat-str.js
+++ b/practice-tdd/repeat-str.js
@@ -1,5 +1,11 @@
-export function repeatStr() {
-  // Your implementation of this function must *not* call String.prototype.repeat (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat).
-  // The goal is to re-implement that function, not to use it.
-  return "hellohellohello";
+export function repeatStr(str, count) {
+  if (count < 0) {
+    throw new Error("Count cannot be negative");
+  }
+  let result = "";
+
+  for (let i = 0; i < count; i++) {
+    result = result + str;
+  }
+  return result;
 }
diff --git a/practice-tdd/repeat-str.test.js b/practice-tdd/repeat-str.test.js
index 8a7036102..94254cf60 100644
--- a/practice-tdd/repeat-str.test.js
+++ b/practice-tdd/repeat-str.test.js
@@ -1,4 +1,6 @@
 // Implement a function repeatStr
+import { test } from "node:test";
+import { strict as assert } from "node:assert";
 import { repeatStr } from "./repeat-str.js";
 // Given a target string `str` and a positive integer `count`,
 // When the repeatStr function is called with these inputs,
@@ -13,7 +15,7 @@ test("should repeat the string count times", () => {
   const str = "hello";
   const count = 3;
   const repeatedStr = repeatStr(str, count);
-  expect(repeatedStr).toEqual("hellohellohello");
+  assert.equal(repeatedStr, "hellohellohello");
 });
 
 // Case: handle count of 1:
@@ -21,12 +23,35 @@ test("should repeat the string count times", () => {
 // When the repeatStr function is called with these inputs,
 // Then it should return the original `str` without repetition.
 
+test("should return the original string when count is 1", () => {
+  const str = "hello";
+  const count = 1;
+  const repeatedStr = repeatStr(str, count);
+  assert.equal(repeatedStr, "hello");
+});
+
 // Case: Handle count of 0:
 // Given a target string `str` and a `count` equal to 0,
 // When the repeatStr function is called with these inputs,
 // Then it should return an empty string.
 
+test("should return an empty string when count is 0", () => {
+  const str = "hello";
+  const count = 0;
+  const repeatedStr = repeatStr(str, count);
+  assert.equal(repeatedStr, "");
+});
+
 // Case: Handle negative count:
 // Given a target string `str` and a negative integer `count`,
 // When the repeatStr function is called with these inputs,
 // Then it should throw an error, as negative counts are not valid.
+
+test("should throw an error when count is negative", () => {
+  const str = "hello";
+  const count = -1;
+
+  assert.throws(() => {
+    repeatStr(str, count);
+  });
+});