The number of adults visiting the museum is 4 times that of children. If there are 420 people visiting the museum, how many children are there?
参观博物馆的成人人数是儿童的4倍，如果一共有420人参观，儿童有多少人？
<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">420 / 5</gadget>
<output>84</output>

<result>84</result>