Question

se da nr..... x=1234567891011121314.........198199200 pprecizati cate cifre are

Answer 1

1-9⇒9cifre;
10-99⇒[99-10+1]·2=[89+1]·2=90·2=180cifre;
100-200⇒[200-100+1]·3=[100+1]·3=101·3=303cifre;
⇒9+180+303
⇒189+303
⇒492[de cifre-are numarul x];