diff --git a/examples/19-adding-a-checkbox/src/app/todo-item/todo-item.component.ts b/examples/19-adding-a-checkbox/src/app/todo-item/todo-item.component.ts
index d706878..d316a15 100644
--- a/examples/19-adding-a-checkbox/src/app/todo-item/todo-item.component.ts
+++ b/examples/19-adding-a-checkbox/src/app/todo-item/todo-item.component.ts
@@ -32,7 +32,7 @@ export class TodoItemComponent implements OnInit {
   completeItem() {
     this.update.emit({
       item: this.item,
-      changes: {completed: !this.item.completed}
+      changes: { completed: !this.item.completed }
     });
   }
 
diff --git a/workshop-todo-list/adding-a-checkbox.md b/workshop-todo-list/adding-a-checkbox.md
index 5f8ba76..f56606c 100644
--- a/workshop-todo-list/adding-a-checkbox.md
+++ b/workshop-todo-list/adding-a-checkbox.md
@@ -43,7 +43,7 @@ export class TodoItemComponent implements OnInit {
   completeItem() {
     this.update.emit({
       item: this.item,
-      changes: {completed: !this.item.completed}
+      changes: { completed: !this.item.completed }
     });
   }
 ```
@@ -98,7 +98,7 @@ And create additional method to handle this update item event. Very similar to `
 
 {% code title="src/app/list-manager/list-manager.component.ts" %}
 ```markup
-updateItem(item, changes) {
+updateItem(item: TodoItem, changes: object) {
   this.todoListService.updateItem(item, changes);
 }
 ```
diff --git a/workshop-todo-list/local-storage.md b/workshop-todo-list/local-storage.md
index 05f8974..8b4fe52 100644
--- a/workshop-todo-list/local-storage.md
+++ b/workshop-todo-list/local-storage.md
@@ -259,13 +259,13 @@ export class TodoListService {
     this.saveList();
   }
 
-  updateItem(item, changes) {
+  updateItem(item: TodoItem, changes: object) {
     const index = this.todoList.indexOf(item);
     this.todoList[index] = { ...item, ...changes };
     this.saveList();
   }
 
-  deleteItem(item) {
+  deleteItem(item: TodoItem) {
     const index = this.todoList.indexOf(item);
     this.todoList.splice(index, 1);
     this.saveList();
diff --git a/workshop-todo-list/remove-item.md b/workshop-todo-list/remove-item.md
index 5c12240..443a60e 100644
--- a/workshop-todo-list/remove-item.md
+++ b/workshop-todo-list/remove-item.md
@@ -63,7 +63,7 @@ Now we just need to add the method `removeItem()` to the `ListManagerComponent`
 
 {% code title="src/app/list-manager/list-manager.component.ts" %}
 ```typescript
-removeItem(item) {
+removeItem(item: TodoItem) {
   this.todoListService.deleteItem(item);
 }
 ```