Question

Calculati numarul cifrelor numarului A=1234567891011...99100

repede dau coroana

Answer 1

N = 1×9 {1...9} + 2×90 {10...99} + 3×1 {100}

N = 1×9 + 2×90 + 3×1

N = 9 + 180 + 3

N = 192

Answer 2

Răspuns:

1,2,3..9 = 9 cifre

10,11,12...99 =90•2=180 cifre

100=3 cifre

9+180+3=192 de cifre in total