By Chris Morris

PHILADELPHIA (CBS) – On today’s APP-tastic and outta SITE – the fifth of our seven best apps of the year…Threes!

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Hit games come and go in the app store, but Threes! is rightfully enjoying a long ride.

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It’s not only smart, or challenging, or baffling, or funny. It’s also utterly addictive.

It’s a math game that doesn’t require a lot of calculations. And it’s a matching game that doesn’t dumb itself down with cartoonish images. Like the best games, it’s easy to understand, but hard to master – but that won’t stop you from trying to do so.

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Check out the Threes! app.