a) 214 -? = 198 -> 214 - 198 = 16
214 - 16 = 198
b) 998 -? = 14 -> 998 - 14 = 984
998 - 984 = 14
c) ? - 200 =104 -> 200 + 104 = 304
304 - 200 = 104
d) ? - 111 = 999 -> 999 + 111 = 1.110
1.110 - 111 = 999
e) ? - 0 = 309 -> 309 - 0 = 309
309 - 0 = 390
f) 14 -? = 0 -> 14 - 0 = 14
14 - 14 = 0
g)26 -? = 1 -> 26 - 1 = 25
26 - 25 = 1
