(1+2+3....+2018):2019

Răspuns :

(2018×2019):2019/2
2018×1/2
2018/2
109

Baftă!

( 1 + 2 + 3 + ...... + 2018 ) : 2019 = 1009

= 2018 × ( 1 + 2018 ) : 2 : 2019 =

= 1009 ×  2019 : 2019 =

= 1009 × 2019 × 1 / 2019 =

= 1009