diff --git a/src/averageTemperatureReading.ts b/src/averageTemperatureReading.ts
new file mode 100644
index 0000000..cb1af66
--- /dev/null
+++ b/src/averageTemperatureReading.ts
@@ -0,0 +1,4 @@
+export function averageTemperatureReading(values: number[]): number {
+  if (values.length === 0) return 0;
+  return values.reduce((a, b) => a + b, 0) / values.length;
+}
diff --git a/src/test/averageTemperatureReading.test.ts b/src/test/averageTemperatureReading.test.ts
new file mode 100644
index 0000000..e65f283
--- /dev/null
+++ b/src/test/averageTemperatureReading.test.ts
@@ -0,0 +1,16 @@
+import { describe, it, expect } from "vitest";
+import { averageTemperatureReading } from "../averageTemperatureReading";
+
+describe("averageTemperatureReading", () => {
+  it("should return the average of multiple values", () => {
+    expect(averageTemperatureReading([10, 20, 30])).toBe(30);
+  });
+
+  it("should return the same value if only one element", () => {
+    expect(averageTemperatureReading([42])).toBe(42);
+  });
+
+  it("should return 0 for an empty array", () => {
+    expect(averageTemperatureReading([])).toBe(0);
+  });
+});
diff --git a/src/test/toggleLed.test.ts b/src/test/toggleLed.test.ts
new file mode 100644
index 0000000..5e14bd4
--- /dev/null
+++ b/src/test/toggleLed.test.ts
@@ -0,0 +1,12 @@
+import { describe, it, expect } from "vitest";
+import { toggleLed } from "../toggleLed";
+
+describe("toggleLed", () => {
+  it("should turn ON when currently OFF", () => {
+    expect(toggleLed(false)).toBe(true);
+  });
+
+  it("should turn OFF when currently ON", () => {
+    expect(toggleLed(true)).toBe(false);
+  });
+});
diff --git a/src/test/turnOnFan.test.ts b/src/test/turnOnFan.test.ts
new file mode 100644
index 0000000..b0d598e
--- /dev/null
+++ b/src/test/turnOnFan.test.ts
@@ -0,0 +1,21 @@
+import { describe, it, expect } from "vitest";
+import { turnOnFan } from "../turnOnFan";
+
+describe("turnOnFan", () => {
+  it("should turn fan ON when temperature is above threshold", () => {
+    expect(turnOnFan(35)).toBe(true);
+  });
+
+  it("should keep fan OFF when temperature is below threshold", () => {
+    expect(turnOnFan(25)).toBe(false);
+  });
+
+  it("should keep fan OFF when temperature is exactly at the threshold", () => {
+    expect(turnOnFan(30)).toBe(false);
+  });
+
+  it("should use custom threshold if provided", () => {
+    expect(turnOnFan(50, 45)).toBe(true);
+    expect(turnOnFan(40, 45)).toBe(false);
+  });
+});
diff --git a/src/toggleLed.ts b/src/toggleLed.ts
new file mode 100644
index 0000000..61d68b1
--- /dev/null
+++ b/src/toggleLed.ts
@@ -0,0 +1,3 @@
+export function toggleLed(state: boolean): boolean {
+  return !state;
+}
diff --git a/src/turnOnFan.ts b/src/turnOnFan.ts
new file mode 100644
index 0000000..2ef56ef
--- /dev/null
+++ b/src/turnOnFan.ts
@@ -0,0 +1,3 @@
+export function turnOnFan(temperature: number, threshold: number = 30): boolean {
+  return temperature > threshold;
+}