tính
a) 1/3 + 3/4 x 2/9
b) 2-(2/5 +2/3)
c) 2/5 : 4/7 +1/3
d)9/13 : 3/26 - 8/13
Những câu hỏi liên quan
Thực hiện phép tính:
1,-4/7 + 2/3x -9/14
2,17/13 - ( 4/13 - 11 )
3, 8 2/7 - ( 3 4/9 + 4 2/7 )
5, ( 2/3 - 1 1/2): 4/3 + 1/2
6, -5/13 + 2/5 + -8/13 + 3/5 - 3/7
7, 6/5 x 3/7 + 6/5 : 7/10 + 6/5
\(1,-\dfrac{4}{7}+\dfrac{2}{3}\times\dfrac{-9}{14}\)
\(=\dfrac{-4}{7}+\dfrac{-18}{42}\)
\(=\dfrac{-4\times6}{7\times6}+\dfrac{-18}{42}\)
\(=\dfrac{-20}{42}+\dfrac{-18}{42}\)
\(=-\dfrac{38}{42}\)
\(=-\dfrac{19}{21}\)
\(2,\dfrac{17}{13}-\left(\dfrac{4}{13}-11\right)\)
\(=\dfrac{17}{13}-\dfrac{4}{13}+11\)
\(=\dfrac{13}{13}+11\)
\(=1+11\)
\(=12\)
\(3,8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\)
\(=\dfrac{58}{7}-\left(\dfrac{31}{9}+\dfrac{30}{7}\right)\)
\(=\dfrac{58}{7}-\dfrac{31}{9}-\dfrac{30}{7}\)
\(=\dfrac{58}{7}-\dfrac{30}{7}-\dfrac{31}{9}\)
\(=\dfrac{28}{7}-\dfrac{31}{9}\)
\(=\dfrac{28\times9}{7\times9}-\dfrac{31\times7}{9\times7}\)
\(=\dfrac{252}{63}-\dfrac{217}{63}\)
\(=\dfrac{35}{63}\)
\(=\dfrac{5}{9}\)
\(5,\left(\dfrac{2}{3}-1\dfrac{1}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2}{3}-\dfrac{3}{2}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{2\times2}{3\times2}-\dfrac{3\times3}{2\times3}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\left(\dfrac{4}{6}-\dfrac{9}{6}\right):\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}:\dfrac{4}{3}+\dfrac{1}{2}\)
\(=\dfrac{-5}{6}\times\dfrac{3}{4}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1}{2}\)
\(=\dfrac{-15}{24}+\dfrac{1\times12}{2\times12}\)
\(=\dfrac{-15}{24}+\dfrac{12}{24}\)
\(=\dfrac{-3}{24}\)
\(=-\dfrac{1}{8}\)
\(6,\dfrac{-5}{13}+\dfrac{2}{5}+\dfrac{-8}{13}+\dfrac{3}{5}-\dfrac{3}{7}\)
\(=\left(\dfrac{-5}{13}+\dfrac{-8}{13}\right)+\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{3}{7}\)
\(=\dfrac{-13}{13}+\dfrac{5}{5}-\dfrac{3}{7}\)
\(=-1+1-\dfrac{3}{7}\)
\(=-\dfrac{3}{7}\)
\(7,\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}:\dfrac{7}{10}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\dfrac{3}{7}+\dfrac{6}{5}\times\dfrac{10}{7}+\dfrac{6}{5}\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+1\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{1\times7}{1\times7}\right)\)
\(=\dfrac{6}{5}\times\left(\dfrac{3}{7}+\dfrac{10}{7}+\dfrac{7}{7}\right)\)
\(=\dfrac{6}{5}\times\dfrac{20}{7}\)
\(=\dfrac{120}{35}\)
\(=\dfrac{24}{7}\)
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Tính:
a, 4 1/3 . 4/9 + 13 2/3 . 4/9
b, 5 1/4 . 3/8 + 10 3/4 . 3/8
c, 6 1/5 . ( -2/7 ) + 14 4/5 . ( -2/7 )
d, 7 1/6 . ( -7/6 ) + 10 5/6 . ( -7/6 )
Bài 1: thực hiện phép tính
a, (3/8 + -3/4 + 7/12) : 5/6 + 1/2
b, -7/3. 5/9+ 4/9. (-3/7)+ 17/7
c,117/13 - (2/5 + 57/13)
d, 2/3 - 0,25 : 3/4 + 5/8 .4
Bài 2: tìm x biết
a, 2/3 x - 1/2 = 1/10
b, -2/3 -1/3 (2x -5) = 3/2
c, (3x -1) (-1/2 x + 7) =0
d, 17/2 - | 2x - 3/4 | =-7/4
e, (x + 1/25) +17/25 = 26/25
\(a,\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\left(-\frac{3}{8}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)
= \(\frac{1}{4}+\frac{1}{2}\)
= \(\frac{3}{4}\)
b)\(-\frac{7}{3}.\frac{5}{9}+\frac{4}{9}.\left(-\frac{3}{7}\right)+\frac{17}{7}\)
=\(-\frac{35}{27}+\left(-\frac{4}{21}\right)+\frac{17}{7}\)
= \(-\frac{35}{27}+\frac{47}{21}\)
= \(\frac{178}{189}\)
c) \(\frac{117}{13}-\left(\frac{2}{5}+\frac{57}{13}\right)\)
= \(\frac{117}{13}-\frac{311}{65}\)
= \(\frac{274}{65}\)
d) \(\frac{2}{3}-0,25:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{4}:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{3}+\frac{5}{2}\)
= \(\frac{1}{3}+\frac{5}{2}\)
= \(\frac{17}{6}\)
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Tính:
a) 2^5 x 13^12 x 7^8 : 27 x 13^10 x 7^9
b) 2^n x 11 x 3 : 6^n x 3
c) 5^5 x 7 x 9^5 : 15^10
d) 7 x 8^10 x 27^9 - 8 x 9^13 x 2^27 : 7 x 6^26 x 2^2 - 2^4 x 8^3 x 27^9
e) 2^2^1^2015
f) 2015^0^2015^0^2015
72-8/3 bằng bao nhiêu số tự nhiên
Tính các tổng sau:
1, S=1-2+3_4+..+25-26
2, S=1-3+5-7+...+49-51
3, S=-1+3-5+7-...-53+55
4, S=2-4+6-8+...+22-24
5, S=-2+4-6+8-...-26+28
6, S=2-5+8-11+...-29+32
7, S=-1+5-9-13-...-41-45
8, S=1-5+9-13+...++89-93
9, S=2-4+6-8+...+202-204
10, S=1-6=11-16+21-26+...+171-176
huhu giúp mình với ạ 2h chiều nay mình phải nộp r =(((
Tính các tổng sau:
1, S=1-2+3_4+..+25-26
S =-1+3-5+7-...-53+55 ( có 28 số hạng )
= (-1+3)+(-5+7)+...+(-53+55) ( có 28:2=14 nhóm )
= 2+2+...+2
= 2 . 14
= 28
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3
S =-1+3-5+7-...-53+55 ( có 28 số hạng )
= (-1+3)+(-5+7)+...+(-53+55) ( có 28:2=14 nhóm )
= 2+2+...+2
= 2 . 14
= 28
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Xem thêm câu trả lời
tính các tổng sau
1) A = 1+7+7^2+7^3+....+7^2007
2) B= 1+4 +4^2+4^3+....+4^100
3) C= 1+3^2 +3^4 +3^6+3^8+....+3^100
4) D= 7+7^3 + 7^5+7^7+7^9+....+7^99
5)E= 2+2^3+2^5+2^7+2^9+....+2^2009
6) B = 1+2^2+2^4+2^6+2^8+....+2^200
7) C= 5+5^3+5^5+5^9+....+5^101
8) D = 13+13^3+13^5+...+13^99
Mình làm mẫu 1 bài rùi bạn tự giải những bài còn lại nha
1, 7A = 7+7^2+7^3+....+7^2008
6A = 7A - A = (7+7^2+7^3+....+7^2008)-(1+7+7^2+....+7^2007) = 7^2008-1
=> A = (7^2008-1)/6
Tk mk nha
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\(A=1+7+7^2+7^3+...+7^{2007}\)
\(\Rightarrow7A=7+7^2+7^3+7^4+...+7^{2008}\)
\(\Rightarrow7A-A=\left(7+7^2+7^3+...+7^{2008}\right)-\left(1+7+7^2+...+7^{2007}\right)\)
\(\Rightarrow6A=7^{2008}-1\)
\(\Rightarrow A=\frac{7^{2008}-1}{6}\)
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4b=4+4^2+4^3+...+4^101
4b-b=(4+4^2+...+4^101)-(1+4+4^2+...+4^100)
3b=4^101-1
b=(4^101-1):3
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Tính :
2/5 + 11/15 =
7/8 - 7/9 =
11/13 x 26/31 =
16/24 : 4 =
30 : 6/5 =
9/16 : 4 =
1/2 : 1/3 x 8/15 =
\(\dfrac{2}{5}+\dfrac{11}{15}=\dfrac{6}{15}+\dfrac{11}{15}=\dfrac{17}{15}\)
\(\dfrac{7}{8}-\dfrac{7}{9}=\dfrac{63}{72}-\dfrac{56}{72}=\dfrac{7}{72}\)
\(\dfrac{11}{13}\times\dfrac{26}{31}=\dfrac{22}{31}\)
\(\dfrac{16}{24}:4=\dfrac{16}{24}\times\dfrac{1}{4}=\dfrac{4}{24}=\dfrac{1}{6}\)
\(30:\dfrac{6}{5}=30\times\dfrac{5}{6}=25\)
\(\dfrac{9}{16}:4=\dfrac{9}{16}\times\dfrac{1}{4}=\dfrac{9}{64}\)
\(\dfrac{1}{2}:\dfrac{1}{3}\times\dfrac{8}{15}=\dfrac{1}{2}\times3\times\dfrac{8}{15}=\dfrac{4}{5}\)
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2/5 + 11/15 = 17/15
7/8 - 7/9 = 7/72
11/13 x 26/31 = 22/31
16/24 : 4 = 1/6
30 : 6/5 = 25
9/16 : 4 = 9/64
1/2 : 1/3 x 8/15 = 3/2 x 8/15 = 4/5
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Tính:
a) 2^5 x 13^12 x 7^8 : 2^7 x 13^10 x 7^9
b) 2^n x 11 x 3 : 6^n x 3
c) 5^5 x 7 x 9^5 : 15^10
d) 7 x 8^10 x 27^9 - 8 x 9^13 x 2^27 : 7 x 6^26 x 2^2 - 2^4 x 8^3 x 27^9
e) 2^2^1^2015
f) 2015^0^2015^0^2015
Bài 1: tínha. 1/3-(-1và2/5)+(-3và1/4) b.5/4-(-3và1/2)-7/10c.3/2-[(-4/7)-(1/2+5/8)]Bài 2: thực hiện phép tính bằng cách hợp lý a. A(1/2-7/13-1/3)+(-6/13+1/2+1và1/3)b.B0,75+2/5+(1/9-1và1/2+5/4)c.(-5/9).3/11+(-13/18).3/11d.(-2/3).3/11+(-16/9).3/11e.(-1/4).(-2/13)-7/24.(-2/13)f.(-1/27).3/7+(5/9).(-3/7)g.(-1/5+3/7):2/11+(-4/5+4/7):2/11bài 3: thực hiện phép tính a.0,3-4/9:4/3.6/5+1b.1+2:(2/3-1/6).(-2,25)c.[(1/4-0,5).2+8/3]:2d.[(3/8-5/12).6+1/3].4e.(4/5-1):3/5-2/3.0,5f.0,8:{0,2-7.[1/6+(5/21-5/14)]}Bài...
Đọc tiếp
Bài 1: tính
a. 1/3-(-1và2/5)+(-3và1/4)
b.5/4-(-3và1/2)-7/10
c.3/2-[(-4/7)-(1/2+5/8)]
Bài 2: thực hiện phép tính bằng cách hợp lý
a. A=(1/2-7/13-1/3)+(-6/13+1/2+1và1/3)
b.B=0,75+2/5+(1/9-1và1/2+5/4)
c.(-5/9).3/11+(-13/18).3/11
d.(-2/3).3/11+(-16/9).3/11
e.(-1/4).(-2/13)-7/24.(-2/13)
f.(-1/27).3/7+(5/9).(-3/7)
g.(-1/5+3/7):2/11+(-4/5+4/7):2/11
bài 3: thực hiện phép tính
a.0,3-4/9:4/3.6/5+1
b.1+2:(2/3-1/6).(-2,25)
c.[(1/4-0,5).2+8/3]:2
d.[(3/8-5/12).6+1/3].4
e.(4/5-1):3/5-2/3.0,5
f.0,8:{0,2-7.[1/6+(5/21-5/14)]}
Bài 4: tính theo cách hợp lý
a.4/15-(2,9-11/15)
b.(-36,75)+(37/10-63,25)-(-6,3)
c. 6,5+(-10/17)-(-7/2)-7/17
d.(-39,1).13/25-60,9.13/25
e. -5/12-3,7-7/12-6,3
f.2,8.-6/13-7,2-2,8.7/13
4:
a: =4/15-2,9+11/15=1-2,9=-1,9
b: \(=-36,75+3,7-63,25+6,3=10-100=-90\)
c: \(=6,5+3,5-\dfrac{10}{17}-\dfrac{7}{17}=10-1=9\)
d: \(=\dfrac{13}{25}\left(-39,1-60,9\right)=\dfrac{13}{25}\left(-100\right)=-52\)
e: =-5/12-7/12-3,7-6,3=-1-10=-11
f: =2,8(-6/13-7/13)-7,2=-2,8-7,2=-10
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