John buys 2 packs of index cards for all his students.  He has 6 classes and 30 students in each class.  How many packs did he buy?
John has 6*30=
<gadget id="calculator">6*30</gadget>
<output>180</output>
180 students.
So he bought 180*2=
<gadget id="calculator">180*2</gadget>
<output>360</output>
360 packs.

<result>360</result>