Вычислите устно:
а) $\snippet{name: op_column_rows, args: ['60 * 6', '- 120', ': 80', '* 30'], solution: '?'}$;
б) $\snippet{name: op_column_rows, args: ['200 : 50', '* 25', '+ 140', ': 60'], solution: '?'}$;
в) $\snippet{name: op_column_rows, args: ['125 * 2', ': 10', '* 40', '- 300'], solution: '?'}$;
г) $\snippet{name: op_column_rows, args: ['490 : 7', '* 20', '+ 210', ': 50'], solution: '?'}$;
д) $\snippet{name: op_column_rows, args: ['40 * 10', ': 50', '* 125', '- 160'], solution: '?'}$.