There are volleyballs, softballs, footballs, and basketballs in the sporting goods store. There are 5 more volleyballs than softballs, twice as many footballs as softballs, and 1 more basketball than footballs. There are 18 volleyballs in total. How many basketballs are there in the store? Only? (Hint: You can draw a tree diagram to solve it)
体育用品商店里有排球、垒球、足球、篮球，其中排球比垒球多5只，足球的只数是垒球的2倍，篮球比足球多1只，排球一共有18只，商店里一共有篮球多少只？(提示：可画树状算图求解)
<gadget id="calculator">18 - 5</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<gadget id="calculator">26 + 1</gadget>
<output>27</output>

<result>27</result>