How much does a social worker make? According to the May 2012 records from the Bureau of Labor Statistics, the mean annual healthcare social worker salary is $51,460, or $24.74 per hour. The lowest ten percent earn $31,410, while the top ten percent make an average of $74,030 annually.
The Leibniz Step Reckoner. Gottfried Leibnizâs 1673 âStep Reckonerâ introduced a design innovation that enabled a single gear to represent any digit from 0 to 9 in just one revolution. This stepped-drum approach dominated calculator design for the next two centuries. Gottfried Leibniz.
In his book Debt: The First 5000 Years, anthropologist David Graeber argues against the suggestion that money was invented to replace barter. The problem with this version of history, he suggests, is the lack of any supporting evidence.