There are 5 boys and 4 girls, and each of them folds 3 planes. How many planes can they fold in total?
男生有5人，女生有4人，每人折3架飞机，他们一共能折多少架架飞机．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<result>27</result>