Question

Va rog!poate pentru cineva e simplu!ex.12

Answer 1

Numerele 1, 2, 3, ..., 100

a) cifra 0 apare cate o data in numerele: 10,20,30,40,50,60,70,80,90, adica in total de 9 ori, si apare de doua ori in numarul 100.

In total, cifra 0 apare de 11 ori

b) cifra 1 apare in numerele: 1, 10, 11 (de doua ori), 12, 13, 14, 15, 16, 17, 18, 19, 21, 31, 41, 51, 61, 71, 81, 91, 100 - in total, apare de 21 ori

c) cifra 5 apare in numerele: 5, 15, 25, 35, 45, 50, 51, 52, 53, 54, 55 (de doua ori), 56, 57, 58, 59, 65, 75, 85, 95 - in total, apare de 20 ori