a, 50-(47+50-18)+(47-18)=50-47-50+18+47-18
=(50-50)+(47-47)+(18-18)
=0+0+0=0
b, 42-56+33-(33+144+42) = 42-56+33-33-144-42
= (42-42)+(33-33)
đến đó mình ko chắc lm nữa, bn tự lm nhé
\(50-\left(47+50-18\right)+\left(47-18\right)\)
\(=50-47-50+18+47-18\)
\(=\left(50-50\right)+\left(47-47\right)+\left(18-18\right)\)
\(=0\)
a ) 50 - 47 +50 -18 +47 -18
= (50+50) - (47 -47) + ( 18+ 18)
=100 - 0 + 36
=136
b) 42 -56 +33 -33 +144 +42
= ( 42 - 42) - (33 - 33) + (56 +144)
=0 + 0 + 200
=200
