A boat goes upstream with a water speed of 2 kilometers and a boat speed of 32 kilometers. How many kilometers does it travel in 4 hours? (ship speed, water speed is calculated per hour)
一只船逆流而上，水速2千米，船速32千米，4小时行多少千米．(船速，水速按每小时算)
<gadget id="calculator">32 - 2</gadget>
<output>30</output>

<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<result>120</result>