Assuming that the long-term potential growth rate is around 3%, the economy would have to grow at 4% for two years to eliminate the gap.

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But Courera hopes to eliminate that gap through the unusual method of having students take exams from the convenience of their laptops, with proctors watching them via webcam.

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That is a huge sum, roughly enough to eliminate the financing gap in the Social Security programme without any other changes.

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