1 + 1 = ?
<>=
1 2
12 36
Những câu hỏi liên quan
A = 1/1x2x3 + 1/2x3x4 + 1/3x4x5 +...+ 1/18x19x20 < 1/4B = 36/1x3x5 + 36/3x5x7 + 36/5x7x9 +...+ 36/25x27x29 < 3C = 1/2^2 + 1/3^2 + 1/4^2 +...+ 1/100^2 < 1D = 1/101 + 1/102 + 1/103 +...+ 1/999 + 1/200 > 7/12
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2A=\(\frac{2}{1.2.3}\)+\(\frac{2}{2.3.4}\)+...+\(\frac{2}{18.19.20}\)
=1/1.2-1/2.3+1/2.3-1/3.4+...+1/18.19-1/19.20
=1/2-1/19.20
A=1/4-1/19.20.2
vậy A<1/4
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A= 7/12 +5/12 : 6 - 11/36
D = 1 và 3/8 + 1/8 : (0,75 - 1/2 ) -25% nhân 1/2
\(A=\dfrac{7}{12}+\dfrac{5}{12}:6-\dfrac{11}{36}=\dfrac{21}{36}+\dfrac{5}{12}.\dfrac{1}{6}-\dfrac{11}{36}=\dfrac{5}{18}+\dfrac{5}{12}.\dfrac{1}{6}=\dfrac{20}{72}+\dfrac{5}{72}=\dfrac{25}{72}\)
\(B=1\dfrac{3}{8}+\dfrac{1}{8}:\left(0,75-\dfrac{1}{2}\right)-25\%.\dfrac{1}{2}=\dfrac{11}{8}+\dfrac{1}{8}:\dfrac{1}{4}-\dfrac{1}{8}=\dfrac{5}{4}+\dfrac{1}{2}=\dfrac{7}{4}\)
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a) Ta có: \(A=\dfrac{7}{12}+\dfrac{5}{12}:6-\dfrac{11}{36}\)
\(=\dfrac{7}{12}+\dfrac{5}{72}-\dfrac{11}{36}\)
\(=\dfrac{42+5-22}{72}\)
\(=\dfrac{25}{72}\)
b) Ta có: \(A=1\dfrac{3}{8}+\dfrac{1}{8}:\left(0.75-\dfrac{1}{2}\right)-25\%\cdot\dfrac{1}{2}\)
\(=\dfrac{11}{8}+\dfrac{1}{8}:\dfrac{1}{4}-\dfrac{1}{4}\cdot\dfrac{1}{2}\)
\(=\dfrac{11}{8}-\dfrac{1}{8}+\dfrac{1}{2}\)
\(=\dfrac{10}{8}+\dfrac{1}{2}\)
\(=\dfrac{5}{4}+\dfrac{2}{4}=\dfrac{7}{4}\)
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Bài 1:
1) 14/12 : (-4,2) - (-5)^2 x 0,2
2? 45 : 2 2/7 + 50% - 1,5
7/12 + 5/12 : 6 - 11/36
1: =7/6:(-21/5)-25*0,2
=-7/6*5/21-5
=-35/126-5
=-5/21-5
=-5/21-105/21=-110/21
3: \(=\dfrac{7}{12}+\dfrac{5}{72}-\dfrac{11}{36}=\dfrac{42+5-22}{72}=\dfrac{25}{72}\)
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a. (3/17 - 2/345 + 5/12 ) - ( -2/345 + 3/17 - 1/12 )
b. -(49/25 +5/36 - 4/123) + (49/25 - 4/123 - 1/36)
a) \(=\frac{3}{17}-\frac{2}{345}+\frac{5}{12}+\frac{2}{345}-\frac{3}{17}+\frac{1}{12}\)
\(=\left(\frac{3}{17}-\frac{3}{17}\right)+\left(\frac{2}{345}-\frac{2}{345}\right)+\left(\frac{5}{12}+\frac{1}{12}\right)\)
\(=\frac{6}{12}=\frac{1}{2}\)
b) \(=-\frac{49}{25}-\frac{5}{36}+\frac{4}{123}+\frac{49}{25}-\frac{4}{123}-\frac{1}{36}\)
\(=\left(-\frac{49}{25}+\frac{49}{25}\right)+\left(\frac{4}{123}-\frac{4}{123}\right)-\left(\frac{5}{36}+\frac{1}{36}\right)\)
\(=-\frac{6}{36}=-\frac{1}{6}\)
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a,1/3+1/4+1/12
b,3/9+12/36-1/3
c,72/36-1/2
d,34-32 1/2
e,68/2-52/4
f,1/2+1/3+1/4+1/5-1/12
g,1/2+1/3+1/4-1/5
h,32/72-21/18
các bạn làm giúp mình bài này nha,làm ngắn gọn nhất ,ai đúng mình tick,cảm ơn mấy bạn
Mình ghi kết quả thôi nhé!
a.2/3
b.1/3
c.3/2
d.18
e.21
f.6/5
g.53/60
h.-13/18
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giải
a) 1/3 +1/4 +1/12 = 2/3
b) 3/9 + 12/39 - 1/3 = 1/3
c) 72/36 - 1/2 = 3/2
d) 34 - 32 và 1/2 = 18
e) 68/2 - 52/4 = 21
g) 1/2 + 1/3 + 1/4 - 1/5 = 53/60
h) 32/72 - 21/18 = (-13/18)
Mình làm ngắn gọn nhanh nhất rồi đó, rút gon luôn rồi. nha
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a,1/3+1/4+1/12
b,3/9+12/36-1/3
c,72/36-1/2
d,34-32 1/2
e,68/2-52/4
f,1/2+1/3+1/4+1/5-1/12
g,1/2+1/3+1/4-1/5
h,32/72-21/18
các bạn làm giúp mình bài này nha,làm ngắn gọn nhất ,ai đúng mình tick,cảm ơn mấy bạn
1/2*6+1/4*9+1/6*12+...+1/36*57+1/38/60.
Bài 20*: Tìm x,y nguyên sao cho.1) 2y. (x+1)=6 2) (2x-1). (y-2)=6 3) (2x-4). 2y= -12 4) (2x-2y).3x=-36 5) (x+y+1). (2y+3)=36
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-36/35:9/14.(-1/2)^3
[6+(1/2)^3 - 1/2]:3/12.
-36/35:9/14.(-1/2)^3
[6+(1/2)^3 - 1/2]:3/12
a: \(=\dfrac{-36}{35}\cdot\dfrac{14}{9}\cdot\dfrac{-1}{8}=\dfrac{36}{9}\cdot\dfrac{14}{35}\cdot\dfrac{1}{8}=4\cdot\dfrac{1}{8}\cdot\dfrac{2}{5}=\dfrac{1}{5}\)
b: \(=\left(6+\dfrac{1}{8}-\dfrac{1}{2}\right)\cdot4\)
\(=\dfrac{48+1-4}{8}\cdot4=\dfrac{45}{2}\)
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