A boat travels 10 kilometers per hour in still water. If the boat travels against the current +3 kilometers per hour, then the speed of the water is + how many kilometers
某船在静水中每小时行驶10千米，如果船逆水每小时行驶+3千米，那么水流的速度是+多少千米
<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<result>7</result>