1) Ta có: \(\left(3104-985\right)-\left(115+3104\right)\)
\(=3104-985-115-3104\)
\(=-1000\)
2) Ta có: \(78\cdot\left(-153\right)\cdot153\cdot78\)
\(=78\cdot\left(-153+153\right)=78\cdot0=0\)
1: (3104 - 985) - (115 + 3104) = 3104 - 985 - 115 - 3104
= -1100
2: 78 . (-153) + 153 . 178 = 78 . ( -153 + 153 ) . 178
= 78 . 0 .178
= 0