Răspuns:
1). 7120, 7220, 7320,7420,7520,7620,7720,7820,7920
7125,7225,7325,7425,7525,7625,7725,7825,7925
2)1302,1304,1306,1308 aici faci la fel numai ca înlocuiești primul nr. Cu 2,3,4,5,6,7,8,9
3)110,210,310,410,510,610,710,810,910 115,215,315,415,515,615,715,815,915