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a) \(-\left(76-35+15\right)+\left[18-27+\left(-17\right)\right]\)
\(=-76+35+15+18-27-17\)
\(=-52\)
b) \(167+\left[127-235-\left(-16\right)\right]+\left(-67\right)\)
\(=167+127-235+16-67\)
\(=8\)
c) \(\left(-19\right)+165-\left[27+\left(-21\right)-\left(+72\right)\right]\)
\(=\left(-19\right)+165-27+21+72\)
\(=212\)
d) \(89.\left(-2\right)+\left[20+\left(-2\right).\left(-5\right)-85\right]\)
\(=\left(-178\right)+\left(20+10-85\right)\)
\(=\left(-178\right)+20+10-85\)
\(=-233\)
\(\left(27+55\right)+\left(345-27-55\right)\)
\(=27+55+345-27-55\)
\(=\left(27-27\right)+\left(55-55\right)+345\)
\(=0+0+345\)
\(=345\)
\(38.65+38.50-38.15\)
\(=38.\left(65+50-15\right)\)
\(=38.100\)
\(=3800\)
\(\left(123-60\right)-\left(2017-60+123\right)\)
\(=123-60-2017+60-123\)
\(=\left(123-123\right)-\left(60-60\right)-2017\)
\(=0-0-2017\)
\(=-2017\)
Bỏ dấu ngoặc rồi tính:
(27 + 55 ) + ( 345 - 27 - 55 )
= 27 + 55 + 345 - 27 - 55
= (27-27) + (55-55) + 345
= 0 + 0 + 345
= 345
Tính nhanh:
38.65 + 38.50 - 38.15
= 38.(65+50-15)
= 38.100
= 3800
Bỏ ngoặc rồi tính:
( 123 - 60 ) - ( 2017 - 60 + 123 )
= 123 - 60 - 2017 + 60 - 123
= (123-123) + (60-60) - 2017
= 0 + 0 - 2017
= 0 - 2017
= -2017
a. (15+37)+(52-37-17) = 15+37+52-37-17
= 15+(37-37)+52-17
= 15+0+35
= 50
Lời giải:
a. $=13-47-13-59+81+35-13$
$=(13-13-13)-(47+59)+(81+35)$
$=-13-106+116=-13+(116-106)=-13+10=-3$
b.
$=345-61+84+61-116-345$
$=(345-345)+(-61+61)-(116-84)$
$=0+0-32=-32$
Bài 1:
Ta có:
(4n-5) \(⋮\)(n-3)
\(\Rightarrow\)(4n-12+17) \(⋮\)(n-3)
\(\Rightarrow\)4(n-3) + 17 \(⋮\)(n-3)
Mà 4(n-3) \(⋮\)(n-3) \(\Rightarrow\)17 \(⋮\)(n-3)
\(\Rightarrow\)n-3 \(\in\)Ư(17)
Ư(17) = { 1 ; -1 ; 17 ; -17 }
\(\Rightarrow\)n-3 \(\in\){ 1 ; -1 ; 17 ; -17 }
\(\Rightarrow\)n \(\in\){ 4 ; 2 ; 20 ; -14 }
Vậy n \(\in\){ 4 ; 2 ; 20 ; -14 }
Bài 2:
a) 7270 - ( 182 + 327 )
= 7270 - 182 - 327
= 7088 - 327
= 6761
b) ( 258 - 89 ) - ( 111 - 90 )
= 258 - 89 - 111 + 90
= 169 - 111 + 90
= 58 + 90
= 148
a) ( 15 + 37 ) + ( 52 - 37 - 17 )
= 15 + 37 + 52 - 37 - 17
= 50
b) ( 38 + 42 + 14 ) - ( 25 - 27 - 15 )
= 38 + 42 + 14 - 25 + 27 + 15
= 111
c) - (21 - 32 ) - ( - 12 + 32 )
= - 21 + 32 + 12 - 32
= - 9
d) - ( 12 + 21 - 23 ) - ( 23 - 21 + 10 )
= - 12 - 21 + 23 - 23 + 21 - 10
= - 22
Trả lời:
a,(15+37) + (52-37-17)
=15+37+52-37-17
=(15+52-17)+(37-37)
=50+0
=50
b,(38+42+14)-(25-27-15)
=38-42+14-25+27+15
=(38+14-42)-(25-25)+27
=10-0+27
=37
c,-(21-32)-(-12+32)
=-21+32+12-32
= -(21+12)+(32-32)
= -9+0
=-9
d,-(12+21-23)-(23-21+10)
= -12-21+23-23+21+10
=(-12+10)-(21-21)-(23-23)
= -2-0+0
= -2
a.( 15 + 37 ) + ( 2 - 37 - 17 )
= 15 + 37 + 52 - 37 - 17
= 15 + (37 - 37) + (52 - 17)
= 15 + 0 + 35
= 50
b.- ( 21 - 32 ) - ( -12 + 32 )
= 21 + 32 + 12 - 32
= ( 21 + 12 ) + ( 32 - 32 )
= 9 + 0
= 9
c ( 38 - 42 + 14) - ( 25 - 27 - 15 )
= 38 - 42 + 14 + (-25) + 27 + 15
= (38 - 42 + 14) + [( -25 ) + 15] + 27
= 10 + (-10) + 27
= 0 + 27
= 27
#ht