Teacher Wang took 71.2 yuan to the stationery store, bought 3 pens with 29.2 yuan, and planned to buy a diary for 7 yuan with the rest of the money. How many such diaries can Mr. Wang buy?
王老师带了71.2元去文具店，用29.2元买了3支钢笔，剩下的钱准备买7元一本的日记本．王老师可以买几本这样的日记本？
<gadget id="calculator">71.2 - 29.2</gadget>
<output>42</output>

<gadget id="calculator">42 / 7</gadget>
<output>6</output>

<result>6</result>