The price of a storybook is 7 yuan, and the price of a small football is three times that of the storybook. How much is the total cost of buying a storybook and a small football?
一本故事书售价7元，一只小足球的售价是故事书的3倍，买一本故事书和一个小足球一共需要多少元？
<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">21 + 7</gadget>
<output>28</output>

<result>28</result>