954+46-(970-(9+13-21))
954+46-(970-(9+13-21))=954+46-(970-1)=954+46-969=1000-969=31
а действие
по действием
954 + 46 - ( 970 - (9 + 13 - 21 )) = 954 + 46 - ( 970 - ( 22 - 21 )) = 954 + 46 - ( 970 - 1 ) = 954 + 46 - 969 = 1000 - 969 = 31 1.9 + 13 = 22 2.22 - 21 = 1 3.970 - 1 = 969 4.954 + 46 = 1000 5.1000 - 969 = 31