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LP
1
21 tháng 2 2023
a) \(\dfrac{2}{5}\cdot\dfrac{1}{7}+\dfrac{2}{5}\cdot\dfrac{5}{7}+\dfrac{2}{5}\)
\(=\dfrac{2}{5}\left(\dfrac{1}{7}+\dfrac{5}{7}+1\right)\)
\(=\dfrac{2}{5}\cdot\dfrac{13}{7}=\dfrac{26}{35}\)
b) \(\dfrac{1}{5}+\dfrac{2}{8}+\dfrac{4}{5}+\dfrac{7}{8}-\dfrac{1}{8}\)
\(=\left(\dfrac{1}{5}+\dfrac{4}{5}\right)+\left(\dfrac{2}{8}+\dfrac{7}{8}-\dfrac{1}{8}\right)\)
\(=1+1=2\)
c)\(\dfrac{24}{36}\cdot\dfrac{10}{12}\cdot36\)
\(=\dfrac{24\cdot10\cdot36}{36\cdot12}=\dfrac{12\cdot2\cdot10\cdot36}{12\cdot36}\)
\(=2\cdot10=20\)
17 tháng 5 2020
\(\frac{7}{9}\times\frac{3}{5}+\frac{3}{5}\times\frac{5}{6}+\frac{3}{5}\times1\)
\(=\frac{3}{5}\times\left(\frac{7}{9}+\frac{5}{6}+1\right)\)
\(=\frac{3}{5}\times\frac{47}{18}\)
\(=\frac{47}{30}\)
#hoktot<3#
1 tháng 3 2022
a, \(\dfrac{20}{15}=\dfrac{4}{3}\)
b, \(\dfrac{6}{15}=\dfrac{2}{5}\)
c, \(\dfrac{42}{30}=\dfrac{7}{5}\)
d, \(\dfrac{40}{35}=\dfrac{8}{7}\)
e, \(\dfrac{42}{42}=1\)
g, \(\dfrac{54}{10}=\dfrac{27}{5}\)
h, \(\dfrac{12}{15}\)
NV
4
18 tháng 5 2022
a: =9/11(7/4+5/4)=9/11x3=27/11
b: \(=\dfrac{28}{5}\cdot\dfrac{5}{8}\cdot\dfrac{5}{4}=\dfrac{28}{8}\cdot\dfrac{5}{4}=\dfrac{140}{32}=\dfrac{35}{8}\)
c: \(=\dfrac{2}{6}+\dfrac{4}{5}\cdot\dfrac{6}{5}-\dfrac{2}{5}=\dfrac{67}{75}\)
18 tháng 5 2022
a,=(7/4+5/4):11/9
=3:11/9
=27/11
b,=28/5.5/4.5/8
=7.5/8
=35/8
c,=1/3+24/25-2/5
=97/75-2/5
=67/75
S
4
LL
c)
d)
3
NA
3
7 tháng 5 2017
a) [ {4/5+1/5+3/10 } +1/7 ] * [3 : 6/5 ] = 13/10 * 5/2 = 13/4
b) = [1+3+5+...99] x [ 2/5 x5 - 1/2 *4 ]=[(99+1)+(98+2)+(97+3) +...+(49+51)] x 0 = 0
NT
1
R
3 tháng 6 2020
a) \(\frac{19}{27}+\frac{9}{7}+\frac{6}{27}+\frac{5}{7}+\frac{2}{27}\)
\(=\left(\frac{19}{27}+\frac{6}{27}+\frac{2}{27}\right)+\left(\frac{9}{7}+\frac{5}{7}\right)\)
\(=1+2=3\)
b) \(\frac{2}{7}+\frac{27}{48}+\frac{7}{16}+\frac{45}{63}\)
\(=\frac{2}{7}+\frac{9}{16}+\frac{7}{16}+\frac{5}{7}\)
\(=\left(\frac{2}{7}+\frac{5}{7}\right)+\left(\frac{9}{16}+\frac{7}{16}\right)\)
\(=1+1=2\)
18 tháng 5 2020
Bài 1:
a) 19/27+9/7+6/27+5/7+2/7
= (19/27+6/27) + (9/7+5/7+2/7)
=1 + 16/7
=23/7
b) 2/7 + 27/48 + 7/16 +45/63
= (2/7 + 45/63) + (27/48 +7/16)
= (2/7 + 5/7) + ( 9/16 + 7/16)
= 1 + 1
=2
c) Tính bằng cách bình thường
Bài 2:
6/11 + x = 1
x = 1-6/11
x = 5/11
18 tháng 5 2020
Bài làm
a) \(\frac{19}{27}+\frac{9}{7}+\frac{6}{27}+\frac{5}{7}+\frac{2}{7}\)
\(=\frac{27}{27}+\frac{16}{7}\)
\(=1+\frac{16}{7}\)
\(=\frac{7}{7}+\frac{16}{7}\)
\(=\frac{23}{7}\)
b) \(\frac{2}{7}+\frac{27}{48}+\frac{7}{16}+\frac{45}{63}\)
\(=\left(\frac{18}{63}+\frac{45}{63}\right)+\left(\frac{27}{48}+\frac{21}{48}\right)\)
\(=\frac{63}{63}+\frac{48}{48}\)
\(=1+1\)
\(=2\)
c) \(\frac{17}{23}+\left(\frac{4}{7}-\frac{6}{13}\right)\)
\(=\frac{17}{23}+\left(\frac{52}{91}-\frac{42}{91}\right)\)
\(=\frac{17}{23}+\frac{10}{91}\)
\(=\frac{1547}{2093}+\frac{230}{2093}\)
\(=\frac{1770}{2093}\)
Bài 2
\(\frac{6}{11}+x=1\)
\(x=1-\frac{6}{11}\)
\(x=\frac{11}{11}-\frac{6}{11}=\frac{5}{11}\)
Vậy \(x=\frac{5}{11}\)
C
7 tháng 4 2022
4/9-5/18 = 8/18 - 5/18 = 3/18 = 1/6
3/5x5/7 = 3/7
4/7:2/7 = 4/7 x 7/2 = 2
VQ
7 tháng 4 2022
4/9-5/18= 8/18 - 5/18 = 3/18 = 1/6
3/5x5/7=15/35 = 3/7
4/7:2/7=4/7 x 7/2 = 4/2 = 2
\(\dfrac{7}{5}\times\dfrac{5}{27}\times\dfrac{6}{7}:\dfrac{5}{27}\)
\(=\dfrac{7}{5}\times\dfrac{6}{7}\times\dfrac{5}{27}\times\dfrac{27}{5}\)
\(=\dfrac{7}{5}\times\dfrac{6}{7}=\dfrac{6}{5}\)
\(\dfrac{7}{5}\times\dfrac{5}{27}\times\dfrac{6}{7}:\dfrac{5}{27}\)
\(C,\dfrac{7}{5}\times\dfrac{5}{27}\times\dfrac{6}{7}\times\dfrac{27}{5}\)
\(C=\left(\dfrac{5}{27}\times\dfrac{27}{5}\right)\times\left(\dfrac{7}{5}\times\dfrac{6}{7}\right)\)
\(C=1\times\dfrac{6}{5}\)
\(C=\dfrac{6}{5}\)