Classmates of a certain grade go to the park to row boats together. If there are 10 people in each boat, then there will be 2 more seats;
某年级的同学集体去公园划船，如果每只船坐10人，那么多出2个座位；如果每只船多坐2人，那么可少租1只船，这样，共需要租多少只船．
<gadget id="calculator">2 - 2</gadget>
<output>0</output>

<gadget id="calculator">10 + 0</gadget>
<output>10</output>

<gadget id="calculator">2 - 10</gadget>
<output>-8</output>

<gadget id="calculator">10 + (-8)</gadget>
<output>2</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<result>4</result>