Ответ:(20 + m) + 34 = m + (20 + 34) = m + 54.235 + (565 + x) = (235 + 565) + x = 800 + x.412 + k + 158 = (412 + 158) + k = 570 + k.1 358 + 2 097 + p = (1 358 + 2 097) + p = 3 455 + p.