THE greatest shortcoming of the human race is our inability to understand the exponential function.

Exponential growth’s stealth factor is nicely illustrated by the story of the man who invented chaturanga, an Indian precursor to chess. He presented his king with a beautifully laid out board divided into 64 squares and when asked to name his reward, requested a grain of wheat to be placed on the first square, two on the next, four on the third, and so on.

It sounded a modest reward, but had the king obliged across the board, he would have given away more than 18 billion billion grains. Fail to understand exponential growth, and our debts can rapidly spiral out of control too