20 + 30 + 40 + 50 + 60 + 70 + 80
= (20 + 80) + (30 + 70) + (40 + 60) + 50
= 100 + 100 + 100 + 50
= 100 x 3 + 50
= 300 + 50
= 350
ai k mik mik k lại
20 + 30 + 40 + 50 + 60 + 70 + 80
= ( 20 + 80 ) + ( 30 + 70 ) + ( 40 + 60 ) + 50
= 100 + 100 + 100 + 50
= 100 x 3 + 50
= 300 + 50
= 350
NHỚ bấm đúng cho mình nha
20 + 30 + 40 + 50 + 60 + 70 + 80
= ( 20 + 80 ) + ( 30 + 70 ) + ( 40 + 60 ) + 50
= 100 + 100 + 100 + 50
= 100 x 3 + 50
= 300 + 50
= 350
20+30+40+50+60+70+80
=(20+80)+(30+70)+(40+60)+50
=100+100+100+50
=350
k minh nha