1: \(-87+\left(-12\right)-\left(-487\right)+512\)
\(=-87+487+512-12\)
\(=\left(-87+487\right)+\left(512-12\right)\)
=400+500
=900
2: \(942-2567+2563-1942\)
\(=\left(942-1942\right)-\left(2567-2563\right)\)
=-1000-4
=-1004
3: \(1152-\left(374-1152\right)+\left(-65+374\right)\)
\(=1152-374+1152-65+374\)
\(=\left(1152+1152\right)+\left(374-374\right)-65\)
=2304-65
=2239
1: −87+(−12)−(−487)+512−87+(−12)−(−487)+512
=−87+487+512−12=−87+487+512−12
=(−87+487)+(512−12)=(−87+487)+(512−12)
=400+500
=900
2: 942−2567+2563−1942942−2567+2563−1942
=(942−1942)−(2567−2563)=(942−1942)−(2567−2563)
=-1000-4
=-1004
3: 1152−(374−1152)+(−65+374)1152−(374−1152)+(−65+374)
=1152−374+1152−65+374=1152−374+1152−65+374
= (1152+1152)+(374−374)−65=(1152+1152)+(374−374)−65
= 2304-65
= 2239
1) -87 + (-12) - (-487) + 512
=-87+(-12)+487+512
=(-87+487)+(512+(-12))
=400+500=900
2) 942 - 2567 + 2563 - 1942
=942+(-2567)+2563+(-1942)
=(942+(-1942))+((-2567)+2563)
=-1000+(-4)=-1004
3) 1152 - (374 - 1152) + (-65 + 374)
=1152-374+1152+(-65)+374
=(1152-1152)+(-374+374)+(-65)
=0+0+(-65)=-65
__________________________HT______________________________-
1) −87+(−12)−(−487)+512
=−87+487+512−12
=(−87+487)+(512−12)
=400+500
=900
2) 942−2567+2563−1942
=(942−1942)−(2567−2563)
=-1000-4
=-1004
3) 1152−(374−1152)+(−65+374)
=1152−374+1152−65+374
=(1152+1152)+(374−374)−65
=2304-65
=2239