There are 5 different story books on the first floor of the bookcase, and 3 different science books on the second floor. Now you want to hold 1 story book and 1 science book. How many different ways are there?
书橱的第一层有5本不同的故事书，第二层有3本不同的科技书，现在要拿1本故事书和1本科技书，有多少种不同的拿法？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<result>15</result>