Tính
1+1/3+/19+1/27+1/81
37,52+4,7×2,3_9,8
Bài 1: tính
1, 1-5+7-8+4-1+5-7+8
2, 14-23+(5+14)-(5-23)+17
3, 12-44+9-3+14-19-9-12
4,22-(4-8+12)+(-8-12+4)
1: =1-1+5-5+7-7+8-8=0
2: =14-23+5+14-5+23+17
=28+17=45
3: =12-12+9-9+14-44-3=-33
4: =22-8-8-12+4
=22-16-8
=-2
Bài \(1\)
\(1)\) \(1-5+7-8+4-1+5-7+8\)
\(=(1-1)+(5-5)+(7-7)+(8-8)\)
\(=0+0+0+0\)
\(=0\)
\(2)\) \(14-23+(5+14)-(5-23)+17\)
\(=14-23+5+14-5+23+17\)
\(=(14+14)+(23-23)+(5-5)+17\)
\(=28+17\)
\(=45\)
\(3)\) \(12-44+9-3+14-19-9-12\)
\(=(12-12)+(9-9)+(14-44)+3\)
\(=-30+3\)
\(=-33\)
\(4)\) \(22-(4-8+12)+(-8-12+4)\)
\(=22-4+8-12-8-12+4\)
\(=22+(4+4)+(8-8)+(-12-12)\)
\(=22-24\)
\(=-2\)
TÍNH
A, 1+ 1/3 + 1/9 + 1/27 + 1/81
B, 37,52 +4,7 * 2,3 - 9,8
A = \(1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}\)
A = \(\frac{81}{81}+\frac{27}{81}+\frac{9}{81}+\frac{3}{81}+\frac{1}{81}\)
A = \(\frac{81+27+9+3+1}{81}\)
A = \(\frac{121}{81}\)
Bài 1:Tính
1) (1/2)^3 (3/2)^2
2) (2/3)^3 (3/2)^5
3) (5/4)^5 (4/5)^7
4) (-5/6)^6 (6/5)^8
5)(-4/3)^3 (9/16)^5
6) (1/3)^4 (-9/2)^6
7)(-4/9)^3 (-27/20)^4
8) (0,2)^4 . 5^6
9) (-4/3)^3 (9/16)^5
10) (-0,2)^3 .(-5)^5
11) (-4)^4 .(0,25)^6
12) $^2 . (0,2)^3
13) (0,5)^2 . 2^4
14) (-0,5)^3 .2^6
15) (-0,5)^5 .(-2)^10
16) (0,125)^2 .8^4
17) (0,125)^5 . (-8)^4
18) (-0,125)^7 . 8^10
19) (-0,1)^4 . 10^7
20) (0,1)^5 . (-10)^10
Giúp mình với ạ,mình cảm ơn ạ
1: =1/8*9/4=9/32
2: =8/27*243/32=9/4
3: =(5/4*4/5)^5*(4/5)^2=16/25
4: \(=\left(-\dfrac{5}{6}\cdot\dfrac{6}{5}\right)^2\cdot\left(\dfrac{6}{5}\right)^2=\dfrac{36}{25}\)
5: \(=\left(-\dfrac{4}{3}\right)^3\cdot\left(\dfrac{3}{4}\right)^{10}=\left(-1\right)\left(\dfrac{3}{4}\right)^7=-\left(\dfrac{3}{4}\right)^7\)
6: \(=\left(\dfrac{1}{3}\cdot\dfrac{-9}{2}\right)^4\left(-\dfrac{9}{2}\right)^2=\left(-\dfrac{3}{2}\right)^4\cdot\dfrac{81}{4}=\dfrac{9}{4}\cdot\dfrac{81}{4}=\dfrac{729}{16}\)
8: =(0,2*5)^4*5^2=25
10: =-0,5^5*2^10
=-0,5^5*2^5*2^5
=-32
13: =(0,5*2)^2*2^2=4
tính
1.\(\sqrt{147}+\sqrt{54}-4\sqrt{27}\)
2.\(\sqrt{28}-4\sqrt{63}+7\sqrt{112}\)
3.\(\sqrt{49}-5\sqrt{28}+\dfrac{1}{2}\sqrt{63}\)
4.\(\left(2\sqrt{6}-4\sqrt{3}-\dfrac{1}{4}\sqrt{8}\right).3\sqrt{6}\)
5.(\(2\sqrt{1\dfrac{9}{16}}-5\sqrt{5\dfrac{1}{16}}\)):\(\sqrt{16}\)
6.\(\left(\sqrt{48}-3\sqrt{27}-\sqrt{147}\right):\sqrt{3}\)
7.\(\left(\sqrt{50}-3\sqrt{49}\right):\sqrt{2}-\sqrt{162}:\sqrt{2}\)
8.\(\left(2\sqrt{1\dfrac{9}{10}}-\sqrt{5\dfrac{1}{10}}\right):\sqrt{10}\)
9.\(2\sqrt{\dfrac{16}{3}}-3\sqrt{\dfrac{1}{27}}-6\sqrt{\dfrac{4}{75}}\)
10.\(2\sqrt{27}-6\sqrt{\dfrac{4}{3}}+\dfrac{3}{5}\sqrt{75}\)
11.\(\dfrac{\sqrt{18}}{\sqrt{2}}-\dfrac{\sqrt{12}}{\sqrt{3}}\)
12.\(\dfrac{\sqrt{27}}{\sqrt{3}}+\dfrac{\sqrt{98}}{\sqrt{2}}-\sqrt{175}:\sqrt{7}\)
13.\(\left(\dfrac{\sqrt{8}}{\sqrt{2}}-\dfrac{\sqrt{180}}{\sqrt{5}}\right).\sqrt{5}-\sqrt{\dfrac{81}{11}}.\sqrt{11}\)
14.\(\sqrt{8\sqrt{3}}-2\sqrt{25\sqrt{12}}+4\sqrt{\sqrt{192}}\)
15.\(\left(3\sqrt{2}-2\sqrt{3}\right)\left(3\sqrt{2}+2\sqrt{3}\right)\)
16.\(\left(1+\sqrt{5}-\sqrt{3}\right)\left(1+\sqrt{5}+\sqrt{3}\right)\)
2 tính
1 + ( -2) + 3 + ( -4) +....+ 19 + ( - 20)
cíu lần 2
1 + (-2) + 3 + (-4) + ... + 19 + (-20)
= (1 - 2) + (3 - 4) + ... + (19 - 20)
= -1 - 1 - ... - 1 (10 chữ số 1)
= -10
đặt A=1+(-2)+3+(-4)+...+19+(-20)
A=(1+3+..+19)-(2+4+..+20) (1)
Đặt B=1+3+...+19
số các số hạng của tôngB là
(19-1) :2+1=10 (số hạng)
tổng B là
B=(19+1).10 / 2
B=100 (2)
Đặt C=2+4+...+20
số các số hạng của tổng C là
(20-2) :2+1=10 (số hạng)
tổng C là
C= (20+2).10 / 2
C= 110 (3)
thay (2) và (3) vào (1) ta được:
A= 100-110
A=-10
Vậy 1 + (-2) + 3 + (-4) +....+19 +(-20)=-10
CHÚC BN HỌC TỐT :>>
1 + (-2) + 3 + (-4) + ... + 19 + (-20)
= (1 - 2) + (3 - 4) + ... + (19 - 20)
= -1 - 1 - ... - 1
= -10
thực hien phép tính
1/2-(1/3+2/3 )
4/9+1/2.2/3
Đáp án :
`-1/2`
Giải thích các bước giải :
`1/2` - (`1/3` + `2/3`)
= `1/2` - 1
= `-1/2`
________________________
Đáp án :
`7/9`
Giải thích các bước giải :
`4/9` + `1/2` . `2/3`
= `4/9` + `1/3`
= `12/27` + `9/27`
= `21/27` = `7/9`
Tính
1 - 1/2;1/2 - 1/3; 1/3 - 1/4; 1/4 - 1/5; 1/5 - 1/6; 1/6 - 1/7
\(1-\dfrac{1}{2}=\dfrac{2}{2}-\dfrac{1}{2}=\dfrac{1}{2}\)
\(\dfrac{1}{2}-\dfrac{1}{3}=\dfrac{3}{6}-\dfrac{2}{6}=\dfrac{1}{6}\)
\(\dfrac{1}{3}-\dfrac{1}{4}=\dfrac{4}{12}-\dfrac{3}{12}=\dfrac{1}{12}\)
\(\dfrac{1}{4}-\dfrac{1}{5}=\dfrac{5}{20}-\dfrac{4}{20}=\dfrac{1}{20}\)
\(\dfrac{1}{5}-\dfrac{1}{6}=\dfrac{6}{30}-\dfrac{5}{30}=\dfrac{1}{30}\)
\(\dfrac{1}{6}-\dfrac{1}{7}=\dfrac{7}{42}-\dfrac{6}{42}=\dfrac{1}{42}\)
`@mt`
Tính
1, 1/12- 2/3
2, 1/6- 1/36
3,-1/6- 2/5
4, 3/4- 1/20
\(1,=\dfrac{1}{12}-\dfrac{4}{12}=\dfrac{3}{12}\\ 2,=\dfrac{6}{36}-\dfrac{1}{36}=\dfrac{5}{36}\\ 3,\dfrac{-1}{6}-\dfrac{2}{5}=\dfrac{-5}{30}-\dfrac{12}{30}=\dfrac{-17}{30}\\ 4,=\dfrac{15}{20}-\dfrac{1}{20}=\dfrac{14}{20}\)
1,=112−412=3122,=636−136=5363,−16−25=−530−1230=−17304,=1520−120=1420
cả lò nhà mik có rảnh ko ạ giải giúp mik vs ạ:)?
Tính
1 1/2.2 1/3+1 1/3.1/2
=3/2*7/3+4/3*1/2
=21/6+4/6=25/6
\(\dfrac{11}{2}.\dfrac{21}{3}+\dfrac{11}{3}.\dfrac{1}{2}\)
\(=\dfrac{77}{2}+\dfrac{11}{6}=\dfrac{121}{3}\)