Вычислите устно:
а) $\snippet{name: op_column_rows, args: ['53 - 46', '* 7', '+ 31', '- 45', ': 7'], solution: '?'}$;
б) $\snippet{name: op_column_rows, args: ['63 - 57', '* 6', '+ 34', '- 30', ': 8'], solution: '?'}$;
в) $\snippet{name: op_column_rows, args: ['81 - 73', '* 8', '+ 26', '- 58', ': 8'], solution: '?'}$;
г) $\snippet{name: op_column_rows, args: ['520 + 280', ': 20', '* 5', ': 25', '* 125'], solution: '?'}$;
д) $\snippet{name: op_column_rows, args: ['600 - 120', ': 4', '* 2', ': 5', '* 20'], solution: '?'}$.