Clarification of array example

site/content/tutorial/02-reactivity/04-updating-arrays-and-objects/app-a/App.svelte

@@ -1,8 +1,8 @@
 <script>
 	let numbers = [1, 2, 3, 4];
 
-	function addNumber() {
-		numbers.push(numbers.length + 1);
+	function addNumber(value) {
+		numbers.push(value);
 	}
 
 	$: sum = numbers.reduce((t, n) => t + n, 0);
@@ -12,4 +12,4 @@
 
 <button on:click={addNumber}>
 	Add a number
-</button>
+</button>

site/content/tutorial/02-reactivity/04-updating-arrays-and-objects/app-b/App.svelte

@@ -1,8 +1,8 @@
 <script>
 	let numbers = [1, 2, 3, 4];
 
-	function addNumber() {
-		numbers = [...numbers, numbers.length + 1];
+	function addNumber(value) {
+		numbers = [...numbers, value];
 	}
 
 	$: sum = numbers.reduce((t, n) => t + n, 0);
@@ -12,4 +12,4 @@
 
 <button on:click={addNumber}>
 	Add a number
-</button>
+</button>

site/content/tutorial/02-reactivity/04-updating-arrays-and-objects/text.md

@@ -7,17 +7,17 @@ Because Svelte's reactivity is triggered by assignments, using array methods lik
 One way to fix that is to add an assignment that would otherwise be redundant:
 
 ```js
-function addNumber() {
-	numbers.push(numbers.length + 1);
+function addNumber(value) {
+	numbers.push(value);
 	numbers = numbers;
 }
 ```
 
 But there's a more *idiomatic* solution:
 
 ```js
-function addNumber() {
-	numbers = [...numbers, numbers.length + 1];
+function addNumber(value) {
+	numbers = [...numbers, value];
 }
 ```