Uncle Wang works from 7:50 am to 11:50 noon, and he makes 30 parts per hour. How many parts does Uncle Wang make in total?
王叔叔从上午7：50工作到中午11：50，他每小时做30个零件，王叔叔一共做多少个零件？
<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<result>120</result>