Question

Enumeră acele numere naturale din patru cifre unde numărul 7 se află de două ori

Answer 1

1177,1277,1377,1477,1577,1677,1877,1977,2177,2277,2377,2477,2577,2677,2877,2977,3177,3277,3377,3477,3577,3677,3877,3977,4177,4277,4377,4577,4677,4877,4977,5177,5277,5377,5477,5577,5677,5877,5977,6177,6277,6377,6477,6577,6677,6877,6977,8177,8277,8377,8477,8577,8677,8877,8977,9177,9277,9377,9477,9577,9677,9877,9977,1771,1772,1773,1774,1775,1776,1778,1779,2771,2772,2773,2774,2774,2775,2776,2778,2779,3771,3772,3773,3774,3775,3776,3778,3779,4771,4772,4773,4474,4775,4776,4778,4779,5771,5772,5773,5774,5775,5776,5778,5779,6771,6772,6773,6774,6775,6776,6778,6779,8771,8772,8773,8774,8775,8776,8778,8779,1077,2077,3077,4077,5077,6077,8077,9077,1770,2770,3770,4770,5770,6770,8770,9770