Ответ:
30 999 + 1 = 31 000.
10 000 − 1 = 9 999.
25 909 + 1 = 25 910.
90 100 − 1 = 90 099.
40 000 − 1 = 39 999.
39 099 + 1 = 39 100.
30 999 + 1 = 31 000.
10 000 − 1 = 9 999.
25 909 + 1 = 25 910.
90 100 − 1 = 90 099.
40 000 − 1 = 39 999.
39 099 + 1 = 39 100.