1 tính
a 18:3-3.(51:17)
b 25-200:50.4
c 77.25+65.77+77.10
d 36.72+36.28-28.100
Bài 1:Tính
a)(-12)+25+75+12;
b)60+12+(-17)+(-43)
c)(-2)+(-87)+(-18)+87;
d)(-1)+(-2)+36+(-17)
Bài 2:Tính
a)(-17) . 6
b)8 . (-125)
c)(-12) . (-15)
d)21 . (- 3)+(- 21 ) . 7
Bài 1:
a: =25+75=100
b: =60-17-43+12=12
c: =-2-18=-20
d: =-3+36-17=36-20=16
Bài 2:
a: =-102
b: =-1000
c: =12x15=180
d: =21x(-10)=-210
B1
a 100
b 12
c -20
d 16
B2
a -102
b -1000
c 180
d -210
Bài 1:Tính
a)(-12)+25+75+12 = 100
b)60+12+(-17)+(-43)=12
c)(-2)+(-87)+(-18)+87=-20
d)(-1)+(-2)+36+(-17)=16
Bài 2:Tính
b)8 . (-125)=-100
c)(-12) . (-15)=180
d)21 . (- 3)+(- 21 ) . 7=-210
1) Tìm x
x - 35% . x = 1/25
2) Tính
a) 17 2/31 - ( 15/17 + 6 2/31 )
b) 27 51/59 - ( 25 51/29 - 1 1/3 )
c) ( 4 5/23 - 2 2/5 + 7 7/13 ) - ( 3 5/23 - 6 6/13 )
d) 8 1/3 + 7,8 + 5 2/3 - 1,8
Bài 1:
Ta có: \(x-35\%\cdot x=\dfrac{1}{25}\)
\(\Leftrightarrow65\%\cdot x=\dfrac{1}{25}\)
\(\Leftrightarrow x=\dfrac{1}{25}:\dfrac{13}{20}=\dfrac{1}{25}\cdot\dfrac{20}{13}=\dfrac{4}{65}\)
Vậy: \(x=\dfrac{4}{65}\)
Bài 2:
a) Ta có: \(17\dfrac{2}{31}-\left(\dfrac{15}{17}+6\dfrac{2}{31}\right)\)
\(=17\dfrac{2}{31}-\dfrac{15}{17}-6\dfrac{2}{31}\)
\(=11+\dfrac{2}{31}-\dfrac{15}{17}\)
\(=\dfrac{5366}{527}\)
Tính nhanh 36.28 + 36.72 + 23.100 + 21.100
36.28 + 36.72 + 23.100 + 21.100
= 36 . 100 + 23 . 100 + 21 . 100
= 80.100
= 8000
=36 . (28+72)+100.(23+21)
=36.100+100.44
=100.(36+44)
=100.80
=8000
= 36 . 100 + 23 . 100 + 21 . 100
= 80.100
= 8000
Tính Nhanh:
36.28+64.141+36.72-64.41
36.28+64.141+36.72-64.41
=36.28+36.72+64.141-64.41
=36.(28+72)+64.(141-41)
=36.100+64.100
=(36+64).100
=100.100
=10000
tích cho mik nha các bn ^^
36(28+72)+64(141-41)
=36.100+64.100
=100(36+64)
=100.100
=10000
Bài 1.Thực hiện các phép tính sau:a)217 320 : 4;
b) 5025:5-25:5 ;
c) 218-180:2:9 ;
d)(328-8):32
Bài 2.Thực hiện phép tính.a) 27 . 75 + 25 . 27 –150
b)12 : { 400 : [500 –(125 + 25 . 7)]}
c) 13 . 17 –256 : 16 + 14 : 7 –1
d) 18 : 3 + 182 + 3.(51 : 17)
ko có bài 3 nhé!!
Bài 4.Thực hiện phép tínha) 375 : {32 –[ 4 + (5. 32–42)]} –14
b) {210 : [16 + 3.(6 + 3. 22)]} –3
Bài 1: Thực hiện các phép tính sau:
\(a)\)Chưa rỏ đề
\(b)\)\(5025\div5-25\div5\)
\(=\)\(1005-5\)
\(=\)\(1000\)
\(c)\)\(218-180\div2\div9\)
\(=\)\(218-10\)
\(=\)\(208\)
\(d)\)\(\left(328-8\right)\div32\)
\(=\)\(320\div32\)
\(=\)\(10\)
Bài 1:
a) ( Tôi không nhìn rõ đầu bài )
b) 5025 : 5 - 25 : 5
= ( 5025 - 25 ) : 5
= 5000 : 5
= 1000
c) 218 - 180 : 2 : 9
= 218 - 180 : ( 2 . 9 )
= 218 - 180 : 18
= 218 - 10
= 208
d) ( 328 - 8 ) : 32
= 320 : 32
= 10
Bài 2: Thực hiện phép tính:
\(a)\)\(27.75+25.27-150\)
\(=\)\(27.\left(75+25\right)-150\)
\(=\)\(27.100-150\)
\(=\)\(2700-150\)
\(=\)\(2550\)
\(b)\)\(12\div\left\{400\div\left[500-\left(125+25.7\right)\right]\right\}\)
\(=\)\(12\div\left\{400\div\left[500-\left(125+175\right)\right]\right\}\)
\(=\)\(12\div\left\{400\div\left[500-300\right]\right\}\)
\(=\)\(12\div\left\{400\div200\right\}\)
\(=\)\(12\div2\)
\(=\)\(6\)
\(c)\)\(13.17-256\div16+14\div7-1\)
\(=\)\(221-16+2-1\)
\(=\)\(206\)
\(d)\)\(18\div3+182+3.\left(51\div17\right)\)
\(=\)\(6+182+3.3\)
\(=\)\(6+182+9\)
\(=\)\(197\)
Bài 1.Tính
a)\(\dfrac{4}{28}\)+\(\dfrac{12}{36}\) b)\(\dfrac{-12}{18}\)+\(\dfrac{15}{-21}\) c)\(\dfrac{14}{28}\)-\(\dfrac{-16}{32}\)-\(\dfrac{17}{51}\)
\(a,\dfrac{1}{7}+\dfrac{1}{3}=\dfrac{3}{21}+\dfrac{7}{21}=\dfrac{10}{21}\\ b,\dfrac{-2}{3}+\dfrac{-5}{7}=\dfrac{-14+\left(-15\right)}{21}=\dfrac{-29}{21}\\ c,\dfrac{1}{2}-\dfrac{-1}{2}-\dfrac{1}{3}=\dfrac{3+3-2}{6}=\dfrac{4}{6}=\dfrac{2}{3}\)
\(a.\dfrac{4}{28}+\dfrac{12}{36}=\dfrac{1}{7}+\dfrac{1}{3}=\dfrac{3}{21}+\dfrac{7}{21}=\dfrac{10}{21}\\ b.\dfrac{-12}{18}+\dfrac{-15}{21}=\dfrac{-2}{3}+\dfrac{-5}{7}=\dfrac{-14}{21}+\dfrac{-15}{21}=\dfrac{-29}{21}\\ c.\dfrac{14}{28}+\dfrac{16}{32}-\dfrac{17}{51}=\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{17}{51}=1-\dfrac{17}{51}=\dfrac{2}{3}\)
\(\dfrac{4}{28}+\dfrac{12}{36}=\dfrac{144}{1008}+\dfrac{336}{1008}=\\ \dfrac{480}{1008}=\dfrac{10}{21}\)
Câu b và c em làm tương tự.
Bài 1:Tính
a) 5/12+3/4+1/3= b) 4/9+25/18+5/6=
a \(\dfrac{3}{2}\)
b \(\dfrac{8}{3}\)
a) \(\dfrac{5}{12}+\dfrac{3}{4}+\dfrac{1}{3}=\dfrac{5}{12}+\dfrac{9}{12}+\dfrac{4}{12}=\dfrac{18}{12}=\dfrac{3}{2}\)
b) \(\dfrac{4}{9}+\dfrac{25}{18}+\dfrac{5}{6}=\dfrac{8}{18}+\dfrac{25}{18}+\dfrac{15}{18}=\dfrac{48}{18}=\dfrac{8}{3}\)
bài 1. Tính
a) 7/-25 + -8/25 b) 6/13 + -15/39 c) 5/7 + 4/-14 d) -8/18 + -15/27
bài 2. Tính
a) 3/5 + -7/4 b) (-2) + -5/8 c) 1/8 + -5/9 d) 6/13 + -14/39 e) -18/24 + 15/21
`@` `\text {Ans}`
`\downarrow`
`1,`
`a)`
`-7/25 + (-8)/25`
`= (-7 - 8)/25`
`= -15/25`
`= -3/5`
`b)`
`6/13 + (-15)/39`
`= 18/39 + (-15)/39`
`= (18 - 15)/39`
`= 3/39`
`= 1/13`
`c)`
`5/7 + 4/(-14)`
`= 10/14 + (-4)/14`
`= (10 - 4)/14`
`= 6/14`
`= 3/7`
`d)`
`-8/18 + (-15)/27`
`= -4/9 + (-5)/9`
`= (-4-5)/9`
`= -9/9 = -1`
`2,`
`a)`
`3/5 + (-7)/4`
`= 12/20 + (-35)/20`
`= (12 - 35)/20`
`=-23/20`
`b)`
`(-2) + (-5)/8`
`= (-16)/8 + (-5)/8`
`= (-16 - 5)/8`
`= -21/8`
`c)`
`1/8 + (-5)/9`
`= 9/72 + (-40)/72`
`= (9-40)/72`
`= -31/72`
`d)`
`6/13 + (-14)/39`
`= 18/39 + (-14)/39`
`= (18 - 14)/39`
`= 4/39`
`e)`
`(-18)/24 + 15/21`
`= (-3)/4 + 5/7`
`= (-21)/28 + 20/28`
`= (-21 + 20)/28`
`= -1/28`
Bài 1. Thực hiện các phép tính sau:
a) 12 : { 400 : [500 – (125 + 25 . 7)]} b) 5 . 22 – 18 : 3
c) 18 : 3 + 182 + 3.(51 : 17) d) 25 . 8 – 12.5 + 170 : 17 - 8
a) 12 : { 400 : [ 500 - ( 125 + 25 . 7 )]}
= 12 : { 400 : [ 500 - ( 125 + 175 )]}
= 12 : { 400 : [ 500 - 300 ]}
= 12 : { 400 : 200 }
= 12 : 2
= 6
b) 5 . 22 - 18 : 3
= 110 - 6
= 104
c) 18 : 3 + 182 + 3 . ( 51 : 17 )
= 6 + 182 + 3.3
= 6 + 182 + 9
= 197
d) 25.8 - 12.5 + 170 : 17 - 8
= 1000 - 60 + 10 - 8
= 940 + 10 - 8
= 940 + 2
= 942