“Groupon is bad at math!” the subject line of Amber’s e-mail to Consumerist proclaimed. I expected to see a poorly-calculated coupon discount or something else related to actual deals. But the error is even weirder than that. Groupon’s Earth Day deals page trumpets that the company is celebrating the planet’s 400th birthday. They offer no explanation for where this number came from, or why it’s missing approximately seven zeroes.