Xiaofang, Xiaojun and Xiaoming made paper flowers together. Each made 18 flowers, 30 of which were red flowers, and the rest were yellow flowers. How many yellow flowers are there?
小芳、小军和小明三个小朋友一起做纸花，每人做了18朵，其中30朵是红花，其余的是黄花，黄花有多少朵？
<gadget id="calculator">18 * 3</gadget>
<output>54</output>

<gadget id="calculator">54 - 30</gadget>
<output>24</output>

<result>24</result>