A pile of Bitcoins are shown here after Software engineer Mike Caldwell minted them in his shop on April 26, 2013 in Sandy, Utah. - 

$99. 100,000 pets. 7500. 50,000. 174 years. Do you know what these numbers mean?

It's time for Silicon Tally. This week, Cory Doctorow, science fiction author and co-editor of Boing Boing, takes the test.

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