<human>:  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?
<bot>: How many laptops were sold? ** There were 72/2 = <<72/2=36>>36 laptops sold.
How many netbooks were sold? ** There were 72/3 = <<72/3=24>>24 netbooks sold.
How many laptops and netbooks were sold? ** So, there were a total of 36 + 24 = <<36+24=60>>60 laptops and netbooks sold.
How many desktop computers were sold? ** Thus, 72 - 60 = <<72-60=12>>12 desktop computers were sold last month.
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