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a: \(=\dfrac{18+6}{27+6}=\dfrac{24}{33}=\dfrac{8}{11}\)
b: \(=\dfrac{21\cdot7\cdot11}{11\cdot3\cdot4}=\dfrac{49}{4}\)
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2 : \(buổi \) \(sáng\) \(bán\) \(dc :\)
\((360 - 142 : 2 =109 l\)
\(buổi\) \(chiều\) \(bán\) \(dc :\)
\(360 - 109 = 251 l\)
\(1,\)
\(a,x\times\dfrac{3}{9}=\dfrac{9}{15}\) \(b,x:\dfrac{1}{2}=\dfrac{5}{6}\)
\(x=\dfrac{9}{15}:\dfrac{3}{9}\) \(x=\dfrac{6}{5}\times\dfrac{1}{2}\)
\(x=\dfrac{81}{45}=\dfrac{9}{5}\) \(x=\dfrac{6}{10}=\dfrac{3}{5}\)
\(2,\) có bạn làm rồi nhé ;>
\(3,\)
\(a,\dfrac{7}{12}+\dfrac{3}{4}\times\dfrac{2}{9}=\dfrac{7}{12}+\left(\dfrac{3}{4}\times\dfrac{2}{9}\right)=\dfrac{7}{12}+\dfrac{1}{6}=\dfrac{7}{12}+\dfrac{2}{12}=\dfrac{7+2}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)
\(b,\dfrac{8}{9}-\dfrac{4}{15}:\dfrac{2}{5}=\dfrac{8}{9}-\left(\dfrac{4}{15}:\dfrac{2}{5}\right)=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{8-6}{9}=\dfrac{2}{9}\)
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a, (3m6dm+ 5dam) x 8
= (3,6m + 50m) x 8
= 53,6m x 8
= 428,8m
b, (9km24m - 71hm4m) : 3
= (9024m - 7104m): 3
= 1920m : 3
= 640m
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`a, 7/24 - 1/6 = 7/24 - 4/24 = 3/24=1/8`
`b, 21/16 : 7/5 = 21/16 xx 5/7 = 15/16`
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\(a,\dfrac{8}{24}-\dfrac{5}{25}=\dfrac{1}{3}-\dfrac{1}{5}=\dfrac{5}{15}-\dfrac{3}{15}=\dfrac{2}{15}\)
\(b,\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{26}{63}\)
a) \(\dfrac{8}{24}-\dfrac{5}{25}=\dfrac{8:8}{24:8}-\dfrac{5:5}{25:5}=\dfrac{1}{3}-\dfrac{1}{5}=\dfrac{5}{15}-\dfrac{3}{15}=\dfrac{2}{15}\)
b) \(\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{18:3}{21:3}-\dfrac{12:3}{27:3}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{54}{63}-\dfrac{28}{63}=\dfrac{26}{63}\)
a) 1/3
b) 1
a, \(\frac{2x3x4x5}{3x4x5x6}\)= \(\frac{2}{6}\)=\(\frac{1}{3}\)
b, \(\frac{9x8x5}{6x4x15}\)=\(\frac{3x3x4x2x5}{2x3x4x3x5}\)=1