Вычислите устно:
а) $\snippet{name: op_column_rows, args: ['500 + 310', ': 90', '* 50', '+ 150'], solution: '?'}$;
б) $\snippet{name: op_column_rows, args: ['1000 : 10', '* 30', '+ 250', ': 50'], solution: '?'}$;
в) $\snippet{name: op_column_rows, args: ['200 + 430', ': 70', '* 40', '+140'], solution: '?'}$;
г) $\snippet{name: op_column_rows, args: ['720 : 90', '* 125', ': 200', '* 120'], solution: '?'}$.