42,56 − 17,798 + 20,7 = 24,762 + 20,7 = 45,462
1)
42,56 − 17,798 = 24,762
$\snippet{name: op_column, sign: '-', x: '42,560', y: '17,798', z: '24,762 '}$
2)
24,762 + 20,7 = 45,462
$\snippet{name: op_column, sign: '+', x: '24,762', y: '20,700', z: '45,462 '}$

(3,07 + 4,78) − 2,09 = 7,85 − 2,09 = 5,76
1)
3,07 + 4,78 = 7,85
$\snippet{name: op_column, sign: '+', x: '3,07', y: '4,78', z: '7,85 '}$
2)
7,85 − 2,09 = 5,76
$\snippet{name: op_column, sign: '-', x: '7,85', y: '2,09', z: '5,76 '}$

34,978 − 21,4059 + 764,3 = 13,5721 + 764,3 = 777,8721
1)
34,978 − 21,4059 = 13,5721
$\snippet{name: op_column, sign: '-', x: '34,9780', y: '21,4059', z: '13,5721 '}$
2)
13,5721 + 764,3 = 777,8721
$\snippet{name: op_column, sign: '+', x: '13,5721', y: '764,3000', z: '777,8721 '}$

30,06 − (7,085 + 8,02) = 30,06 − 15,105 = 14,955
1)
7,085 + 8,02 = 15,105
$\snippet{name: op_column, sign: '+', x: '7,085', y: '8,020', z: '15,105 '}$
2)
30,06 − 15,105 = 14,955
$\snippet{name: op_column, sign: '-', x: '30,060', y: '15,105', z: '14,955 '}$