Răspuns:
1+2+3+....+2018 :2019
=2018*2019:2:2019
=1009*1 (am grupat 2019:2019 si 2018:2)
=1009
( 1 + 2 + 3 + ... + 2018 ) : 2019 =
( 2018 × 2019 : 2 ) : 2019 =
( 4074342 : 2 ) : 2019 =
2037171 : 2019 = 1009
