diff --git a/topics/about_strings.js b/topics/about_strings.js
index 18f9c68a..16d9d787 100644
--- a/topics/about_strings.js
+++ b/topics/about_strings.js
@@ -32,3 +32,58 @@ test("slice", function() {
     var fruit = "apple pie";
     equal(__, fruit.slice(0,5), 'what is the value of fruit.slice(0,5)?');
 });
+
+test("indexOf", function() {
+    var fruit = "apple pie";
+    equal(__, fruit.indexOf('a'), 'what is the index of character a in the string?');
+    equal(__, fruit.indexOf('a', 3), 'what is the index of character a in the string starting at offset 3?');
+    equal(__, fruit.indexOf('p'), 'what is the index of character p in the string?');
+    equal(__, fruit.indexOf('p', 5), 'what is the index of character p in the string starting at offset 5?');
+    equal(__, fruit.indexOf('z'), 'what is the index of character z in the string?');
+});
+
+test("lastIndexOf", function() {
+    var fruit = "apple pie";
+    equal(__, fruit.lastIndexOf('a'), 'what is the last index of character a in the string?');
+    equal(__, fruit.lastIndexOf('a', 3), 'what is the last index of character a in the string starting at offset 3?');
+    equal(__, fruit.lastIndexOf('p'), 'what is the last index of character p in the string?');
+    equal(__, fruit.lastIndexOf('z'), 'what is the index of character z in the string?');
+});
+
+test("trim", function() {
+    var fruit = "   apple pie  ";
+    equal(__, fruit.trim(fruit), 'what is the trimmed string?');
+    equal(__, fruit.trim("pie     "), 'what is the trimmed string?');
+    equal(__, fruit.trim("   apple"), 'what is the trimmed string?');
+});
+
+test("trimLeft", function() {
+    var fruit = "   apple pie  ";
+    equal(__, fruit.trimLeft(fruit), 'what is the trimmed string?');
+    equal(__, fruit.trimLeft("pie     "), 'what is the trimmed string?');
+    equal(__, fruit.trimLeft("   apple"), 'what is the trimmed string?');
+});
+
+test("startsWith", function() {
+    var fruit = "apple pie";
+    equal(__, fruit.startsWith("app"), 'does the string start with?");
+    equal(__, fruit.startsWith("ap"), 'does the string start with?");
+    equal(__, fruit.startsWith("pie"), 'does the string start with?");
+    equal(__, fruit.startsWith("pie", 5), 'does the string start with?");
+});
+
+test("endsWith", function() {
+    var fruit = "apple pie";
+    equal(__, fruit.endsWith("pie"), 'does the string end with?");
+    equal(__, fruit.endsWith("app"), 'does the string end with?");
+    equal(__, fruit.endsWith("ie"), 'does the string end with?");
+    equal(__, fruit.endsWith("le", 5), 'does the string end with?");
+});
+
+test("substring", function() {
+    var fruit = "apple pie";
+    equal(__, fruit.substring(0, 5), 'what is the substring?');
+    equal(__, fruit.endsWith(5), 'what is the substring?');
+    equal(__, fruit.endsWith(5, 0), 'what is the substring?');
+    equal(__, fruit.endsWith(7), 'what is the substring?');
+});