Question

VA ROG FRUMOS AJUTATIMA !!!
A=7+97+997+.........+99.....97
(de 2005 ori)
Aflati suma cifrelor A

Answer 1

Răspuns

Explicație pas cu pas:

$\displaystyle\\A=7+97+997+...+99...97\\A=10-3+100-3+1000-3+.....+1\underbrace{0...0}-3\\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~de~2006~ori\\A= \underbrace{1111....1}0 -3\cdot 2006\\ ~~~~~de~2006~ori\\A=111...10 -6018\\ A=\underbrace{111..1}05092\\~~~~de~2002~ori\\Suma~cifrelor~lui~A~este: 2002+5+9+2=2018 (ca~sa~vezi` :))~~~)$