Deirdre McCloskey (“Equality is irrelevant if the poor are growing richer”, August 12) seeks to absolve the world’s super-rich of responsibility for the world’s poor, but she botches the maths. A correct calculation shows that just the 85 wealthiest people in the world could indeed make a major contribution to ending the massive suffering of the world’s poorest.

The top 85 people have a combined net worth of $2tn according to the most recent Forbes survey. Assume, as she does, that these assets are all put to work for the world’s poor. With a standard real payout of 5 per cent per year, as with the endowment of a foundation or university, the annual flow is $100bn.

As of 2015, around 1bn people (the so-called bottom billion) will live in extreme poverty using the World Bank’s standard definition. With around five people per household, this means around 200m households below the poverty line. The wealth of the 85 billionaires would thereby enable a flow of $500 per poor household per year.