3.22 tính 1 cách hợp lí
a) 232 - (581+132-331)
b) [12+(-57)] - [-57-(-12)]
1.Tính 1 cách hợp lí
a, 232-(581+132-331)
b,[12+(-57)] - [-57-(-12)]
a: \(232-\left(581+132-331\right)\)
\(=232-581-132+331\)
\(=\left(232-132\right)+\left(-581+331\right)\)
\(=100-250\)
=-150
b: \(\left[12+\left(-57\right)\right]-\left[-57-\left(-12\right)\right]\)
\(=12+\left(-57\right)+57+\left(-12\right)\)
\(=\left(12-12\right)+\left(57-57\right)\)
=0+0
=0
Tính một cách hợp lí:
a) 232 - (581 + 132 - 331);
b) [12 + (-57)) – [-57- (-12)].
a) 232 - (581 + 132 - 331)
= 232 - 581 - 132 + 331
= (232 - 132) - (581 - 331)
= 100 - 250
= -(250 - 100)
= -150
b) [12 + (-57)] - [-57 - (-12)]
= 12 - 57 + 57 - 12
= (12 - 12) + (57 - 57)
= 0 + 0
= 0
tính 1 cách hợp lí
a)232 - (581 + 132 - 331)
b)[12 + (-57)] - [-57 - (-12)
làm đc cho 1tick
`a, 232 - ( 581 + 132 -331)`
`= 232 - 581 - 132 +331`
`= (232-132) +(-581 + 331)`
`= 100 -250`
`=-150`
`b, [12+ (-57)] - [-57-(-12)]`
`= 12+ (-57) - (-57+12)`
`= 12+ (-57) + 57 -12`
`= (12-12) + (-57+57)`
`= 0+0`
`=0`
`a)232-(581+132-331)`
`=232-581-132+331`
`=(232-132)-(581-331)`
`=100-250`
`=-150`
`b)[12+(-57)]-[-57-(-12)]`
`=(12-57)-(-57+12)`
`=12-57+57-12`
`=(12-12)-(57-57)`
`=0-0`
`=0`
Tính một cách hợp lí :
a) 232 - (581 + 132 - 331)
b) [12 + (-57)] - [-57 - (-12)
a) \(232-\left(581+132-331\right)\)
\(=232-581-132+331\)
\(=\left(232-132\right)+\left(331-581\right)\)
\(=100-250\)
\(=-150\)
b) \(\left[12+\left(-57\right)\right]-\left[-57-\left(-12\right)\right]\)
\(=12-57+57-12\)
\(=\left(12-12\right)+\left(57-57\right)\)
\(=0+0\)
\(=0\)
a) 232 - ( 581 + 132 - 331 )
= 232 - 581 - 132 + 331
= ( 232 - 132 ) - ( 581 - 331 )
= 100 - 250
= -150
a) 232 – (581 + 132 – 331)
= 232 – 581 – 132 + 331
= (232 – 132) – (581 – 331)
= 100 – 250
= -150
b) [12 + (-57)] - [- 57 - (-12)]
= (12 – 57) – (- 57 + 12)
= 12 - 57 + 57 - 12
= (12 – 12) + (57 – 57)
= 0 + 0
= 0
3.21: bỏ dấu ngoặc rồi tính a) (56 -27) - (11+ 28 -16) b) 28+ (19- 28) - ( 32 - 57) 3.20 : tìm một cách hợp lí a) 21 -22 +23 - 24 b) 125 - ( 115 - 99) 3.22: tính một cách hợp lí a) 232 - (581 + 123 - 331 ) b) [ 12+ ( -57) ] - [ -57 - ( -12) 3.33: tính giá trị các biểu thức a) ( 23+x) - ( 56-x) với x =7 b) 25 -x - ( 29 + y - 8) với x =13 ,x= 11
Bài 3.21:
b: =28+19-28-32+57
=76-32
=44
Tính:
a, -321 + (-29 ) - 142 - (-72)
b, 214 - (-36) + (-305)
c, 232 - (581 + 132 - 331)
d, [ 12+ (-57)] - [-57 - (-12)
a, -321 + (-29 ) - 142 - (-72) = -321 - 29 - 142 + 72 = -420.
b, 214 - (-36) + (-305) = 214 + 36 - 305 = -55.
c, 232 - (581 + 132 - 331) = 232 - 581 - 132 + 331 = -150.
d, [ 12+ (-57)] - [-57 - (-12) = 12 - 57 + 57 - 12 = 0.
bài 1: tính hợp lí
a) 5 x 72 x 10 x 2 b) 40 x 125 c) 4 x 2021 x 25 d) 16 x 6 x 25
bài 2: tính nhanh
a) 24 x 57 + 43 x 24 b) 12 x 19 + 80 x 12 +12
c) (36 x 15 x 169) : (5 x 18 x13) d) (44 x 52 x 60) : ( 11 x 13 x 15)
bài 3: tìm X
a) X - 280 : 35 = 5 x 54 b) ( X - 280) : 35 = 54 : 4
c) ( X - 128 + 20 ) : 192 = 0 d) 4 x ( X + 200) = 460 + 85 x 4
bài 4: thực hiện phép tính
a) 7/12 - 5/12 b) 8/11 + 19/11 c) 3/8 + 5/12 d) 3/4 + 7/12
bài 5: tìm x
a) X - 6/7 = 5/2 b) 12/7 : X + 2/3 = 7/5
`@` `\text {Ans}`
`\downarrow`
`1,`
`a)`
`5 \times 72 \times 10 \times 2`
`= 5 \times 2 \times 10 \times 72`
`= 10 \times 10 \times 72`
`= 100 \times 72`
`= 7200`
`b)`
`40 \times 125`
`= 4 \times 10 \times 25 \times 5`
`= (5 \times 10) \times (4 \times 25)`
`= 50 \times 100`
`= 5000`
`c)`
`4 \times 2021 \times 25`
`= (4 \times 25) \times 2021`
`= 100 \times 2021`
`= 202100`
`d)`
`16 \times 6 \times 25`
`= 4 \times 4 \times 6 \times 25`
`= (4 \times 25) \times 4 \times 6`
`= 100 \times 24`
`= 2400`
`2,`
`a)`
`24 \times 57 + 43 \times 24`
`= 24 \times (57+43)`
`= 24 \times 100`
`= 2400`
`b)`
`12 \times 19 + 80 \times 12 +12`
`= 12 \times (19 + 80 + 1)`
`= 12 \times 100`
`= 1200`
`c)`
`(36 \times 15 \times 169) \div (5 \times 18 \times 13)`
`= 36 \times 15 \times 169 \div 5 \div 18 \div 13`
`= 6 \times 6 \times 3 \times 5 \times 13 \times 13 \div 5 \div 3 \times 6 \div 13`
`= (6 \div 6) \times (3 \div 3) \times (5 \div 5) \times (13 \div 13) \times 6 \times 13`
`= 6 \times 13`
`= 78`
`d)`
`(44 \times 52 \times 60) \div ( 11 \times 13 \times 15)`
`= 44 \times 52 \times 60 \div 11 \div 13 \div 15`
`= 4 \times 11 \times 13 \times 4 \times 15 \times 4 \div 11 \div 13 \div 15`
`= (11 \div 11) \times (13 \div 13) \times (15 \div 15) \times 4 \times 4 \times`
`= 4 \times 4 \times 4`
`= 64`
`3,`
`a)`
`x - 280 \div 35 = 5 \times 54`
`x - 8 = 270`
`x = 270 + 8`
`x = 278`
`b)`
`(x - 280) \div 35 = 54 \div 4`
`(x - 280) \div 35 = 13,5`
`x - 280 = 13,5 \times 35`
`x - 280 = 472,5`
`x = 472,5 + 280`
`x = 752,5`
`c)`
`(x - 128 + 20) \div 192 = 0`
`x - 128 + 20 = 0 \times 192`
`x - 128 + 20 = 0`
`x - 108 = 0`
`x = 0 + 108`
`x = 108`
`d)`
`4 \times (x + 200) = 460 + 85 \times 4`
`4 \times (x+200) = 460 + 340`
`4 \times (x+200) = 800`
`x + 200 = 800 \div 4`
`x + 200 = 200`
`x = 200 - 200`
`x = 0`
`4,`
`a)`
`7/12 - 5/12`
`= (7 - 5)/12`
`= 2/12`
`= 1/6`
`b)`
`8/11 + 19/11`
`= (8+19)/11`
`= 27/11`
`c)`
`3/8 + 5/12`
`= 9/24 + 10/24`
`= 19/24`
`d)`
`3/4 + 7/12`
`= 9/12 + 7/12`
`= 16/12`
`= 4/3`
`5,`
`a)`
`x - 6/7 = 5/2`
`x = 5/2 + 6/7`
`x = 47/14`
`b)`
`12/7 \div x + 2/3 = 7/5`
`12/7 \div x = 7/5 - 2/3`
`12/7 \div x = 11/15`
`x = 12/7 \div 11/15`
`x = 180/77`
`@` `\text {Kaizuu lv uuu}`
bài 1
a, -23-12 b, 12-(5-7) c, 283+581-282-531
a,-100-12 b, 15-(-9)-4 c,3758+57-3769-66
a, -123-20 b, -17-(8-25) c, 2575+37-2575+29
a, 43-(-53) b, -5+10-12-5 c, 17+33+(-37)+(-33)
a, 14-(-20) b, (1456+23)-1456 c, -4+(-10)+25+(-11)
a, -15-(-17) b, (2354-45)-2354 c, 42-69+17+(-42)-17
a, 143-(-123) b, -2021-(57-2021) c, (-2)+(-370)+(-8)+370
giúp mình với ạ
a: -23-12=-(23+12)=-35
a: -100-12=-(100+12)=-112
a: -123-20=-(123+20)=-143
a: 43-(-53)=43+53=96
a: 14-(-20)=14+20=34
a: -15-(-17)=-15+17=17-15=2
a: 143-(-123)=143+123=266
b: 12-(5-7)=12-(-2)=12+2=14
b: 15-(-9)-4=11+9=20
b: -17-(8-25)=-17-8+25=-25+25=0
b: -5+10-12-5=(10-5-5)-12=0-12=-12
b: (1456+23)-1456=1456-1456+23=0+23=23
b: (2354-45)-2354=2354-45-2354=-45
b: -2021-(57-2021)=-2021-57+2021=-57
c: 283+581-282-531=(283-282)+(581-531)=50+1=51
c: 3758+57-3769-66
=(3758-3769)+(57-66)
=(-11)+(-9)
=-(11+9)
=-20
c: 2575+37-2575+29
=37+29
=66
c: 17+33+(-37)+(-33)
=(17-37)+(33-33)
=0+(-20)
=-20
c: -4+(-10)+25+(-11)
=(-4-10-11)+25
=25-25
=0
c: 42-69+17+(-42)-17
=(42-42)+(17-17)+(-69)
=-69
c: (-2)+(-370)+(-8)+370
=(-2-8)+(-370+370)
=-10+0
=-10
a) (35-15). (-4) + 24.(-13-17)
b) (-13).(57-34) + 57. (13-45)
.Thực hiện phép tính một cách hợp lí nhất:
a) (-8). (-12). (-125)
b) (-134) + 51.134 + (-134).48
c) 45.(24) + (-10).(-12)
Bài 3. Thực hiện tính hợp lí
a) 47.36+47.64 b) (−43+1315−126)−(1315+57)
𝑎) 19.35−19.2+67.19 b) (−25+117)+(−117)+25
a, = 47 . ( 36 + 64 )
= 47 . 100 = 4700
b, = -43 + 1315 - 126 - 1315 - 57
= ( - 43 - 57 ) - 126
= - 100 - 126
= -226
c, = 19 . ( 35 - 2 + 67 )
= 19 . 100 = 1900
d, = -25 + 117 - 117 + 25
= 0