Đáp án:
`a,`
`1152-(374+1152)+(-65+374)`
`= 1152 - 374 - 1152 - 65+374`
`=-374+374 +1152-1152-65`
`=0+0-65`
`=-65`
`b,`
`-23.63+23.21-58.23`
`=23.(63+21-58)`
`=23.(-100)`
`=-23100`
`c,`
`-72.(12-56)+12.(-56+72)`
`=-72.(-44)+12.16`
`=3366`
`d,`
`1-2+3-4+5-6+.......+19-20`
`=(1-2)+(3-4)+(5-6)+...+(19-20)`
`=(-1) + (-1) + .............+ ( -1)`
`=(-1) .10= -10`