Найди неизвестное а)208+...=389 б) 26*9-...=104 ...-428=165 ...+480:8=570 639-...=27 68:4+...=158 ...+58=498 ...-7*18=57

a) 208 + x = 389; x = 389 - 208 = 181; б) 26 * 9 - x = 104; 234 - x = 104; x = 234 -  104 = 130; в) x - 428 = 165; x = 165 + 428 = 593; г) x + 480/8 = 570; x + 60 = 570; x = 570 - 60 = 510; д) 639 - x = 27; x = 639 - 27 = 612; е) 68/4 + x = 158; 17 + x = 158; x = 158 - 17 = 141; з) x + 58 = 498; x = 498 - 58 = 440; ж) x - 7*18 = 57; x - 126 = 57; x = 57 + 126 = 183.