👤

cat face suma 11+22+33...+198 plz rapid coroana

Răspuns :

11+22+33...+198  = 
11
×( 1+ 2+ 3 + ...+18) =
11× 18×19 : 2 = 
1881
11+22+33...+198=

=11(1+2+3+...+18)

=11
·18·19:2

=1881