perl -e 'print sprintf( "%f",     66.5 * ( ( 100 + 19 ) / 100 ) ), "\n79.135000"'
perl -e 'print sprintf( "%.2f",   66.5 * ( ( 100 + 19 ) / 100 ) ), " <-- wrong, expected 79.14\n"'

perl -e 'print sprintf( "%f",     66.5 * (   100 + 19 ) / 100   ), "\n79.135000"'
perl -e 'print sprintf( "%.2f",   66.5 * (   100 + 19 ) / 100   ), " <-- ok = 79.14\n"'