50 - 51 + 40 -41 + 30 - 31 + 60
= (60 - 51) + (50 - 41) + (40 - 31)+30
= 9 + 9 + 9 + 30
= 57
50-51+40-41+30-31+60
= 9+9+9+60
= 9x3+60
= 27+60
= 87
50-51+40-41+30-31+60
=(-1)+(-1)+(-1)+60
=57
\(50-51+40-41+30-31+60\)
\(=\left(50-41\right)+\left(40-31\right)+\left(60-51\right)+30\)
\(=9+9+9+30\)
\(=27+30\)
\(=57\)
T mik mik T lại hứa đó
TL
=(60-51)+(50-41)+(40-31)--3
=9+9+9+30
=57
Hok tốt nhen