diff --git a/kotlin-basic/src/main/kotlin/10_Inheritance.kt b/kotlin-basic/src/main/kotlin/10_Inheritance.kt
new file mode 100644
index 00000000..197ab8e0
--- /dev/null
+++ b/kotlin-basic/src/main/kotlin/10_Inheritance.kt
@@ -0,0 +1,40 @@
+
+open class Dog {
+    open var age: Int = 0
+
+    open fun bark() {
+        println("멍멍")
+    }
+}
+
+class Bulldog(final override var age: Int = 0): Dog() {
+
+    final override fun bark() {
+        super.bark()
+        println("컹컹")
+    }
+}
+
+abstract class Developer {
+
+    abstract var age: Int
+    abstract fun code(language: String)
+}
+
+class Backend(override var age: Int = 0): Developer() {
+
+    override fun code(language: String) {
+        println("I code with $language")
+    }
+}
+
+fun main() {
+//    val dog = Bulldog(age = 2)
+//    println(dog.age)
+//    dog.bark()
+
+    val backendDeveloper = Backend(age = 20)
+    println(backendDeveloper.age)
+    backendDeveloper.code("Kotlin")
+}
+
diff --git a/kotlin-basic/src/main/kotlin/9_Class.kt b/kotlin-basic/src/main/kotlin/9_Class.kt
new file mode 100644
index 00000000..907a5141
--- /dev/null
+++ b/kotlin-basic/src/main/kotlin/9_Class.kt
@@ -0,0 +1,27 @@
+class Coffee (
+    var name: String = "", // 기본값 지정
+    var price: Int = 0,
+) {
+    val brand: String
+        get() {
+            return  "스타벅스"
+        }
+
+    var quantity: Int = 0
+        set(value) {
+            if (value > 0) {
+                field = value // 필드에 접근하여 데이터 저장
+            }
+        }
+}
+
+class EmptyClass
+
+fun main() {
+    val coffee = Coffee();
+    coffee.name = "아이스 아메리카노"
+    coffee.price = 2000
+    coffee.quantity = 1
+
+    println("${coffee.brand}: ${coffee.name} ${coffee.quantity}개 가격은 ${coffee.price}원")
+}