There are 18 footballs in the gymnasium, and the number of volleyballs is three times that of footballs. How many footballs and volleyballs are there in this stadium?
体育馆有足球18个，排球个数是足球的3倍．这个体育馆有足球和排球共多少个．
<gadget id="calculator">18 * 3</gadget>
<output>54</output>

<gadget id="calculator">54 + 18</gadget>
<output>72</output>

<result>72</result>