31 students are rowing, divided into 3 big boats and 4 small boats, each big boat has 5 students, how many students are in each small boat? (column equation)
31名学生划船，分乘3只大船和4只小船，每只大船坐5名学生，每只小船坐几名学生？(列方程)
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">31 - 15</gadget>
<output>16</output>

<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<result>4</result>