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a: =>3/8x6/3<x<20/21x21/4
=>3/4<x<5
hay \(x\in\left\{1;2;3;4\right\}\)
b: =>56/42<x<11/2
=>4/3<x<11/2
nên \(x\in\left\{2;3;4;5\right\}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: =>3/8x6/3<x<20/21x21/4
=>3/4<x<5
hay \(x\in\left\{1;2;3;4\right\}\)
b: =>56/42<x<11/2
=>4/3<x<11/2
nên \(x\in\left\{2;3;4;5\right\}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Lời giải:
$=\frac{1}{4}+\frac{1}{8}\times \frac{4}{3}\times \frac{21}{16}$
$=\frac{1}{4}+\frac{7}{32}=\frac{15}{32}$
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a) \(\frac{3}{16}+\frac{4}{15}+\frac{5}{16}+\frac{1}{15}\)
\(=\left(\frac{3}{16}+\frac{5}{16}\right)+\left(\frac{4}{15}+\frac{1}{15}\right)\)
\(=\frac{1}{2}+\frac{1}{3}\)
\(=\frac{5}{6}\)
b) \(\frac{6}{7}\times\frac{8}{15}\times\frac{7}{6}\times\frac{15}{16}\)
\(=\left(\frac{6}{7}\times\frac{7}{6}\right)\times\left(\frac{8}{15}\times\frac{15}{16}\right)\)
\(=1\times\frac{1}{2}=\frac{1}{2}\)
c) \(\frac{19}{20}\times\frac{13}{21}+\frac{9}{20}\times\frac{8}{21}\)
\(=\frac{19\times13}{20\times21}+\frac{9\times8}{20\times21}\)
\(=\frac{247}{420}+\frac{72}{420}\)
\(=\frac{319}{420}\)
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1.\(\dfrac{8}{11}+\dfrac{8}{33}\times\dfrac{3}{4}=\dfrac{8}{11}+\dfrac{8\times3}{33\times4}=\dfrac{8\times12}{11\times12}+\dfrac{8\times3}{33\times4}=\dfrac{8\times15}{132}=\dfrac{120}{132}=\dfrac{10}{11}\)
2.\(\dfrac{7}{9}\times\dfrac{3}{14}:\dfrac{5}{8}=\dfrac{7}{9}\times\dfrac{3}{14}\times\dfrac{8}{5}=\dfrac{4}{15}\)
3.\(\dfrac{5}{12}-\dfrac{7}{32}:\dfrac{21}{16}=\dfrac{5}{12}-\dfrac{7}{32}\times\dfrac{16}{21}=\dfrac{5}{12}-\dfrac{1}{6}=\dfrac{5-2}{12}=\dfrac{3}{12}=\dfrac{1}{4}\)
`@V.Tr.V`
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b, 3/5 + 4/7 + 2/8 + 10/25 + 9/21 + 28/16
= 3/5 + 4/7 + 2/8 + 2/5 + 3/7 + 14/8
= (3/5 + 2/5) + ( 4/7 + 3/7) + ( 2/8 + 14/8)
= 1 + 1 + 7/4
= 2 + 7/4 = 15/4
c , 8/7 + 7/6 + 5/8 + 10/12 + 24/28 + 6/16
= c , 8/7 + 7/6 + 5/8 + 5/6 + 6/7 + 1/2
= (8/7 + 6/7) + (7/6 + 5/6) + 5/8 + 1/2
= 14/7 + 12/6 + 5/8 + 1/2
= 2 + 2 + 5/8 + 1/2
= 4 + 9/8 = 41/8
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11/15 + 8/5= Tính phân số
6/7 - 5/21=
25/4 x 16/100
7 x 2/49 =
4/3 : 2/9
5/8 : 25 =
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một thửa ruộng hình vuông có chu vi là 100 mét.Người ta cấy lúa trung bình là 1 mét vuông thu hoạch được 12/25 kg.hỏi trên thửa ruộng đó người ta thu hoạch được bao nhiêu tạ thóc
a, 7/15 +4/5 =7/15+12/15 = 19/15
b,2/3-3/8=16/24-9/24=7/24
C,4/7x21/16:5/8=4/7x21/16x8/5=6/5
D,13x42x11/33x26x35=1/5
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98775 - 32 x 85
=98775 -2720
=96055
67500 - 24 x 236
= 67500 -5664
=61836
568 + 101598 : 287
= 568 +354
=922
6875 + 980 -180
=7855 -180
=7675
\(\dfrac{2}{5}+\dfrac{3}{10}-\dfrac{1}{2}\)
\(=\dfrac{7}{10}-\dfrac{1}{2}\)
= \(\dfrac{1}{5}\)
\(\dfrac{8}{11}+\dfrac{8}{33}x\dfrac{3}{4}\)
\(=\dfrac{8}{11}+\dfrac{2}{11}\)
\(=\dfrac{10}{11}\)
\(\dfrac{7}{9}x\dfrac{3}{14}:\dfrac{5}{8}\)
\(=\dfrac{1}{6}:\dfrac{5}{8}\)
\(=\dfrac{1}{6}x\dfrac{8}{5}\)
\(=\dfrac{8}{30}\)
\(=\dfrac{4}{15}\)
\(\dfrac{5}{12}-\dfrac{7}{32}:\dfrac{21}{16}\)
\(=\dfrac{5}{12}-\dfrac{7}{32}x\dfrac{16}{21}\)
\(=\dfrac{5}{12}-\dfrac{1}{6}\)
\(=\dfrac{5}{12}-\dfrac{2}{12}\)
\(=\dfrac{3}{12}=\dfrac{1}{4}\)
21/4 x 16/4 x 1/2 x 3/8
= 21x16x1x3 / 4x4x2x8
= 1008 / 256
= 63/16
= 63/16