table { border-collapse: collapse; width: 300px; margin: auto; font-size: 20px; font-weight: bold; } td { border: 1px solid black; padding: 10px; text-align: center; } input[type="text"] { width: 100%; height: 50px; font-size: 24px; text-align: right; border: none; } input[type="button"] { width: 100%; height: 50px; font-size: 24px; border: none; background-color: #F2F2F2; cursor: pointer; } input[type="button"]:hover { background-color: #E6E6E6; } Calculator