diff --git a/samples/calc-02/index.js b/samples/calc-02/index.js
index 89de0db..8001346 100644
--- a/samples/calc-02/index.js
+++ b/samples/calc-02/index.js
@@ -53,28 +53,28 @@ const keypadKeys = [
 ];
 
 const functionKeys = [
-	{ label: 'x²', action: 'sqr', className: 'key-default' },
-	{ label: 'yˣ', action: 'pow', className: 'key-default' },
-	{ label: '1/x', action: 'recip', className: 'key-default' },
+	{ label: 'x²', action: 'sqr', className: 'key-default', title: 's' },
+	{ label: '√x', action: 'sqrt', className: 'key-default', title: 'r' },
+	{ label: '1/x', action: 'recip', className: 'key-default', title: 'v' },
 	{ label: '%', action: 'mod', className: 'key-default' },
-	{ label: '√x', action: 'sqrt', className: 'key-default' },
-	{ label: 'y√x', action: 'root', className: 'key-default' },
-	{ label: '10ˣ', action: 'pow10', className: 'key-default' },
+	{ label: 'yˣ', action: 'pow', className: 'key-default', title: 'S' },
+	{ label: 'y√x', action: 'root', className: 'key-default', title: 'R' },
+	{ label: '10ˣ', action: 'pow10', className: 'key-default', title: 'u' },
 	{ label: '', spacer: true },
-	{ label: 'log', action: 'log', className: 'key-default' },
-	{ label: 'ln', action: 'ln', className: 'key-default' },
-	{ label: 'eˣ', action: 'exp', className: 'key-default' },
+	{ label: 'log', action: 'log', className: 'key-default', title: 'l / L' },
+	{ label: 'ln', action: 'ln', className: 'key-default', title: 'n / N' },
+	{ label: 'eˣ', action: 'exp', className: 'key-default', title: 'e / E' },
 	{ label: '', spacer: true },
 ];
 
 const trigoKeys = [
-	{ label: 'sin', action: 'sin', className: 'key-default' },
-	{ label: 'cos', action: 'cos', className: 'key-default' },
-	{ label: 'tan', action: 'tan', className: 'key-default' },
+	{ label: 'sin', action: 'sin', className: 'key-default', title: 'i' },
+	{ label: 'cos', action: 'cos', className: 'key-default', title: 'o' },
+	{ label: 'tan', action: 'tan', className: 'key-default', title: 'a' },
 	{ label: '', spacer: true },
-	{ label: 'asin', action: 'asin', className: 'key-default' },
-	{ label: 'acos', action: 'acos', className: 'key-default' },
-	{ label: 'atan', action: 'atan', className: 'key-default' },
+	{ label: 'asin', action: 'asin', className: 'key-default', title: 'I' },
+	{ label: 'acos', action: 'acos', className: 'key-default', title: 'O' },
+	{ label: 'atan', action: 'atan', className: 'key-default', title: 'A' },
 	{ label: '', spacer: true },
 ];
 
@@ -280,7 +280,7 @@ function execute(name) {
 	}
 }
 
-function createKeyButton({ label, input, action, spacer, className }) {
+function createKeyButton({ label, input, action, spacer, className, title }) {
 	if (spacer) {
 		const div = document.createElement('div');
 		return div;
@@ -289,6 +289,7 @@ function createKeyButton({ label, input, action, spacer, className }) {
 	button.type = 'button';
 	button.textContent = label;
 	button.className = className;
+	if (title) button.title = title;
 	button.addEventListener('click', () => {
 		if (input) {
 			inputToX(input);
@@ -340,8 +341,8 @@ function handleKeyboard(event) {
 		S: 'pow',
 		r: 'sqrt',
 		R: 'root',
-		v: 'recip',
-		u: 'pow10',
+		x: 'recip',
+		d: 'pow10',
 		l: 'log',
 		L: 'log',
 		n: 'ln',
diff --git a/samples/calc-02/visual-portrait.md b/samples/calc-02/visual-portrait.md
index 0c9e345..6fe8abc 100644
--- a/samples/calc-02/visual-portrait.md
+++ b/samples/calc-02/visual-portrait.md
@@ -24,11 +24,11 @@
 
 ```
 ┌──────────── Keypad ─────────────┐
-| +/- | Clear | Esc   | backspace |
-| 7   | 8     | 9     | /         |
-| 4   | 5     | 6     | *         |
-| 1   | 2     | 3     | -         |
-| 0   | .     | Enter | +         |
+| Clear | Backspace | Esc | Enter |
+| 7     | 8         | 9   | /     |
+| 4     | 5         | 6   | *     |
+| 1     | 2         | 3   | -     |
+| 0     | .         | +/- | +     |
 └─────────────────────────────────┘
 ```
 
@@ -36,9 +36,9 @@
 
 ```
 ┌──────────── Functions ──────────┐
-| x^2  | y^x   | 1/x   | %        |
-| √x   | y√x   | 10^x  |          |
-| log  | ln    |       |          |
+| x^2  | √x    | 1/x   | %        |
+| y^x   | y√x  | 10^x  |          |
+| log  | ln    | e^x   |          |
 └─────────────────────────────────┘
 ```