During Children's Day, the Science and Technology Museum is open to school students free of charge for 3 days, and about 1,400 people visit it every day. How many people visited the Science and Technology Museum for free during Children's Day?
儿童节期间，科技馆免费向在校学生开放3天，每天大约有1400人来参观，儿童节期间一共有多少人免费参观了科技馆？
<gadget id="calculator">1_400 * 3</gadget>
<output>4_200</output>

<result>4_200</result>