There are 25 people on the bus, 6 people get off at the bank, and 3 people get on the bus. 7 people get off at the supermarket and 4 people get on the bus. How many people are there on the bus now?
公交车上有25人，到银行下车6人，上车3人．到超市下车7人，上车4人．现在公交车上一共有几人？
<gadget id="calculator">25 - 6</gadget>
<output>19</output>

<gadget id="calculator">3 - 7</gadget>
<output>-4</output>

<gadget id="calculator">19 + (-4) + 4</gadget>
<output>19</output>

<result>19</result>