Giups MIK NHA MN :
1) -(251 × 3+ 281)+3 × 251-(1-281)
2) [2,5 × 0,38.(-0,4)] -[-0,125×3,15×8]
3) [(-20,83)×0,2+(-9,17)×0,2+(-9,17)×0,2] : [2,47×0,5-(-3,53)×0,5]
4) -12,7×32,6+2,7×12,8+12,7×2,6+2,7×17,2
Giups MIK NHA MN : 1) -(251 × 3+ 281)+3 × 251-(1-281) 2) [2,5 × 0,38.(-0,4)] -[-0,125×3,15×8] 3) [(-20,83)×0,2+(-9,17)×0,2+(-9,17)×0,2] : [2,47×0,5-
By Adeline
Đáp án:
`1)`
`-(251xx3+281)+3xx251-(1-281)`
`=-251xx3-281+3xx251-1+281`
`=3xx(251-251)+(281-281)-1`
`=3xx0+0-1`
`=-1`
`2)`
`[2,5xx0,38.(-0,4)]-[-0,125xx3,15xx8]`
`=[(2,5xx(-0,4))xx0,38]-[(-0,125xx8)xx3,15]`
`=(-1)xx0,38-(-1)xx3,15`
`=-0,38+3,15`
`=2,77`
`3)`
`[(-20,83)xx0,2+(-9,17)xx0,2+(-9,17)xx0,2]:[2,47xx0,5-(-3,53)xx0,5]`
`=[0,2xx(-20,83-9,17-9,17)]:[0,5xx(2,47-(-3,53)]`
`=[0,2xx(-39,17)]:[0,5xx6]`
`=(-7,834):3`
`=-(3917)/(1500)`
_______________________________________________________
(bỏ một `-9,17xx0,2`)
`[(-20,83)xx0,2+(-9,17)xx0,2]:[2,47xx0,5-(-3,53)xx0,5]`
`=[0,2xx(-20,83-9,17)]:[0,5xx(2,47-(-3,53)]`
`=[0,2xx(-30)]:[0,5xx6]`
`=(-6):3`
`=-2`
`4)`
`-12,7xx32,6+2,7xx12,8+12,7xx2,6+2,7xx17,2`
`=12,7xx(-32,6+2,6)+2,7xx(12,8+17,2)`
`=12,7xx(-30)+2,7xx30`
`=30xx(-12,7+2,7)`
`=30xx(-10)`
`=-300`
1)-(251 3+ 281)+3×251-(1-281)
=-251-281+3×251-1+281
=(-251×3+3×251)+(-281+281)-1
=0+0-1
=-1
3)
[ ( – 20,83 ) . 0,2 + ( -9,17 ) . 0,2 ] : [ 2,47 . 0,5 – ( -3,53 ) – 0,5 ]
= { 0,2 . [( – 20,83) + (-9,17) } : [ 2,47 . 0,5 + 3,53 – 0,5 ]
= { 0,2 . (-30) } : [ 2,47 . 0,5 – 0,5 + 3,53 ]
= -6 : [ 0,5 . (2,47-1 ) + 3,53 ]
= -6 : [ 0,5 . 1,47+ 3,53 ]
= -6 : [ 0,735 + 3,53 ]
= -6 : 4,265
= -1200/853
4)12,7.(−32,6)+2,7.12,8+12,7.2,6+2,7.17,2
=12,7(−32,6+2,6)+2,7(12,8+17,2)A
=12,7.(−30)+2,7.30
=30(−12,7+2,7)
=30.(−10)
=−300