100 + 30 + 50 + 50 + 80 + 789
= 130 + 100 + 869
= 230 + 869
= 1099
100+30+50+50+80+789
=130+(50+50)+80+789
=130+100+80+789
=230+80+789
=310+789
=1099
\(100+30+50+50+80+789\)
\(=100+30+\left(50+50\right)+80+789\)
\(=130+100+869\)
\(=230+869\)
\(=1099\)
100+30+50+50+80+789
=(100+30+50+50)+80+789
=230+789
=1019
mik làm đúng hk?