Ответ:\(12\cdot3=36\);\(13\cdot4=52\);\(18:2=9\);\(12:3=4\);\(340+298=638\);\(392-204=188\);\(597-319=278\);\(905-698=207\).Ответ: 36; 52; 9; 4; 638; 188; 278; 207.