a, ( - 23 ) + 15 + 18 + 23
=(-23) + 23+ 15+ 18
= 0+15+18
= 33
b, 815 + [ 95 + ( - 815 ) + ( - 45 ) ]
=815 + 95 + ( - 815 ) + ( - 45 )
= 815+(-815) + 95 + (-45)
= 0 +95 +(-45)
= 50
c, ( 1267 - 196 ) - ( 267 + 304 )
= 1267 - 196 - 267 - 304
= 1267 - 267 - (196 + 304)
= 1000 - 500
= 500
d, 1152 - ( 374 + 1152 ) + ( - 65 + 374 )
= 1152 - 374 - 1152 + ( - 65 + 374 )
= 1152 - 1152 - 374 + ( -65 + 374 )
= 0 - 374 + (-65) + 374
= -374 + 374 + (-65)
= 0 + (-65)
= -65
Chúc bạn học tốt :)))))))