$804 \overset{3}{-} (267 \overset{1}{+} 438) \overset{4}{+} (525 \overset{2}{-} 56) = 804 - 705 + 469 = 99 + 469 = 568$
1)
$\snippet{name: op_column, sign: '+', x: '267', y: '438', z: '705'}$
2)
$\snippet{name: op_column, sign: '-', x: '525', y: '56', z: '469'}$
3)
$\snippet{name: op_column, sign: '-', x: '804', y: '705', z: '99'}$
4)
$\snippet{name: op_column, sign: '+', x: '99', y: '469', z: '568'}$
 
$749 \overset{1}{:} 749 \overset{4}{+} 0 \overset{2}{:} 319 \overset{5}{-} 219 \overset{3}{*} 0 = 1 + 0 - 0 = 1$