A stationery bag is 12 yuan, and a pen holder is 7 yuan. Xiao Ming brought 100 yuan and bought 6 stationery bags. How many pen holders can he buy with the remaining money?
一个文具袋12元，一个笔筒7元．小明带了100元钱，买了6个文具袋，剩下的钱可以买多少个笔筒？
<gadget id="calculator">12 * 6</gadget>
<output>72</output>

<gadget id="calculator">100 - 72</gadget>
<output>28</output>

<gadget id="calculator">28 / 7</gadget>
<output>4</output>

<result>4</result>