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a)\(\left(\dfrac{5}{6}+\dfrac{3}{8}\right)\times\dfrac{2}{7}\)
\(=\dfrac{29}{24}\times\dfrac{2}{7}\)
\(=\) \(\dfrac{29}{84}\)
b) \(\dfrac{6}{7}\times\dfrac{2}{3}\div\dfrac{5}{7}\)
= \(\dfrac{4}{7}\div\) \(\dfrac{5}{7}\)
= \(\dfrac{4}{5}\)
c) \(\dfrac{8}{9}+\dfrac{3}{4}\times\dfrac{4}{9}\)
= \(\dfrac{8}{9}+\dfrac{1}{3}\)
= \(\dfrac{5}{9}\)
Cô tích xanh cho lisa blackpink vì câu a, b đúng. Còn câu c thì em làm như sau:
c, \(\dfrac{8}{9}\) + \(\dfrac{3}{4}\) \(\times\) \(\dfrac{4}{9}\)
= \(\dfrac{8}{9}\) + \(\dfrac{1}{3}\)
= \(\dfrac{8}{9}\) + \(\dfrac{3}{9}\)
= \(\dfrac{11}{9}\)
\(a.\frac{7}{5}+\frac{4}{7}-\frac{9}{10}=\frac{98}{70}+\frac{40}{70}-\frac{63}{70}=\frac{98+40-63}{70}=\frac{75}{70}\)\(=\frac{15}{14}\)
\(b.2+\frac{3}{4}x\frac{8}{5}=2+\frac{6}{5}=\frac{16}{5}\)
\(c.\frac{9}{8}-\frac{6}{5}:\frac{8}{5}=\frac{9}{8}-\frac{6}{5}x\frac{5}{8}=\frac{9}{8}-\frac{6}{8}=\frac{3}{8}\)
1/3.4 + 1/4.5 + 1/5.6 + 1/6.7 + 1/7.8 + 1/8.9
= 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 + 1/6 - 1/7 + 1/7 - 1/8 + 1/8 - 1/9
= 1/3 - 1/9
= bam may tinh di hihi :3
#Giải :
\(=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{8}-\frac{1}{9}\)
\(=\frac{1}{3}-\frac{1}{9}=\frac{9}{27}-\frac{3}{27}=\frac{6}{27}\)
P/S : Bước 1 có thể viết hết,xin lỗi vì không viết đầu bài.
#By_Ami.
a)\(\dfrac{8}{5}+\dfrac{7}{6}+\dfrac{5}{9}-2\)
\(=\dfrac{144}{90}+\dfrac{105}{6}+\dfrac{50}{90}-\dfrac{180}{90}=\dfrac{119}{90}\)
b) \(3-\dfrac{5}{6}-\dfrac{4}{9}+\dfrac{32}{24}\)
\(=3-\dfrac{5}{6}-\dfrac{4}{9}+\dfrac{4}{3}\)
\(=\dfrac{54}{18}-\dfrac{15}{18}-\dfrac{8}{18}+\dfrac{24}{18}=\dfrac{55}{18}\)
6/7 * 5/8*7/3*7/6*8/5
= 6*5*7*7*8 /7*8*3*6*5
=1*1*7*1*1/1*1*3*1*1
= 7/3
4/3:5/4:6/5:7/6:8/7:9/8
=4/3*4/5*5/6*6/7*7/8*8/9
=4/3*4*1/9
=16/27
$= (\dfrac{48}{30} + \dfrac{25}{30} ) : \dfrac{7}{6}$
$= \dfrac{73}{30} : \dfrac{7}{6}$
$= \dfrac{73}{30} \times \dfrac{6}{7}$
$= \dfrac{438}{210}$
$= \dfrac{73}{35}$
\(\left(\dfrac{8}{5}+\dfrac{5}{6}\right):\dfrac{7}{6}\)
\(=\left(\dfrac{48}{30}+\dfrac{25}{30}\right):\dfrac{7}{6}\)
\(=\dfrac{73}{30}:\dfrac{7}{6}\)
\(=\dfrac{73}{30}\times\dfrac{6}{7}\)
\(=\dfrac{438}{210}\)
\(=\dfrac{73}{35}\)