diff --git a/.DS_Store b/.DS_Store
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diff --git a/1-exercise-solutions/lesson-07/duygu/function.js b/1-exercise-solutions/lesson-07/duygu/function.js
new file mode 100644
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+++ b/1-exercise-solutions/lesson-07/duygu/function.js
@@ -0,0 +1,51 @@
+/* 7a */
+
+function greet() {
+  console.log("Hello!");
+}
+
+greet();
+
+/* 7b */
+
+function greet(name) {
+  console.log(`Hello ${name}!`);
+}
+
+greet("Simon");
+greet("John");
+greet("Angela");
+
+/* 7c */
+
+function greet(name) {
+  if (!name) {
+    console.log("Hi there!");
+  } else {
+    console.log(`Hello ${name}`);
+  }
+ 
+}
+
+greet("Duygu");
+greet("");
+greet();
+
+/* 7d */
+
+function convertToFahrenheit(celsius) {
+  let fahrenheit = (celsius * 9/5) + 32;
+  console.log(`${celsius} degree is ${fahrenheit} fahrenheit.`);
+}
+
+convertToFahrenheit(25);
+
+/* 7e */
+
+function convertToCelsius (fahrenheit) {
+  let celsius = (fahrenheit -32) * 5 / 9;
+  console.log(`${fahrenheit} is ${celsius} celsius.`);
+}
+
+convertToCelsius (86);
+