1 + 1 = ?
<>=
1 2
12 36
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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
\(A=\dfrac{7}{12}+\dfrac{5}{12}:6-\dfrac{11}{36}=\dfrac{21}{36}+\dfrac{5}{12}.\dfrac{1}{6}-\dfrac{11}{36}=\dfrac{5}{18}+\dfrac{5}{12}.\dfrac{1}{6}=\dfrac{20}{72}+\dfrac{5}{72}=\dfrac{25}{72}\)
\(B=1\dfrac{3}{8}+\dfrac{1}{8}:\left(0,75-\dfrac{1}{2}\right)-25\%.\dfrac{1}{2}=\dfrac{11}{8}+\dfrac{1}{8}:\dfrac{1}{4}-\dfrac{1}{8}=\dfrac{5}{4}+\dfrac{1}{2}=\dfrac{7}{4}\)
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: \(=\dfrac{7}{12}+\dfrac{5}{72}-\dfrac{11}{36}=\dfrac{42+5-22}{72}=\dfrac{25}{72}\)
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) \(=-\frac{49}{25}-\frac{5}{36}+\frac{4}{123}+\frac{49}{25}-\frac{4}{123}-\frac{1}{36}\)
\(=\left(-\frac{49}{25}+\frac{49}{25}\right)+\left(\frac{4}{123}-\frac{4}{123}\right)-\left(\frac{5}{36}+\frac{1}{36}\right)\)
\(=-\frac{6}{36}=-\frac{1}{6}\)
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
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
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: \(=\left(6+\dfrac{1}{8}-\dfrac{1}{2}\right)\cdot4\)
\(=\dfrac{48+1-4}{8}\cdot4=\dfrac{45}{2}\)
=2
1<2
12<36
k mik nha
=2
1<2
12<36