Mr. Lu owns a computer store. For last month, half of their sales are laptops, one-third are netbooks, and the rest are desktop computers. If Mr. Lu's store was able to sell a total of 72 computers, how many of them are desktop computers?
There were 72/2 = 
<gadget id="calculator">72/2</gadget>
<output>36</output>
36 laptops sold.
There were 72/3 = 
<gadget id="calculator">72/3</gadget>
<output>24</output>
24 netbooks sold.
So, there were a total of 36 + 24 = 
<gadget id="calculator">36+24</gadget>
<output>60</output>
60 laptops and netbooks sold.
Thus, 72 - 60 = 
<gadget id="calculator">72-60</gadget>
<output>12</output>
12 desktop computers were sold last month.

<result>12</result>