Mom takes Xiaoming to see grandma by long-distance bus. It departs at 8 am and arrives at 12 noon. The speed of the car is 84 kilometers per hour. How many kilometers is it from Xiaoming's house to grandma's house?
妈妈带小明坐长途汽车去看奶奶，早上8时出发，中午12时到达，汽车每小时的速度是84千米，从小明家到奶奶家有多少千米？
<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">4 * 84</gadget>
<output>336</output>

<result>336</result>