The fourth grade prepared 420 yuan to buy gifts for Children's Day. After buying for 4 classes, there is still 100 yuan left to buy gifts for the group garden show. How much is the average gift for each class?
四年级准备了420元买六一礼物．买给4个班后，还剩100元买集体游园节目的礼物，平均每班买礼物多少元？
<gadget id="calculator">420 - 100</gadget>
<output>320</output>

<gadget id="calculator">320 / 4</gadget>
<output>80</output>

<result>80</result>