38 * b - 989
b = 54
38 * 54 - 989 = 2052 - 989 = 1063
b = 612
38 * 612 - 989 = 23 256 - 989 = 22 267
b = 304
38 * 304 - 989 = 11 552 - 989 = 10 563
(105 * 18) : d + 205
d = 5
(105 * 18) : 5 + 205 = 1890 : 378 + 205 = 583
d = 15
(105 * 18) : 15 + 205 = 1890 : 15 + 205 = 126 + 205 = 331
d = 45
(105 * 18) : 45 + 205 = 1890 : 45 + 205 = 42 + 205 = 247