Tính
M: \(\dfrac{32x50}{48x75}\)=\(\dfrac{16x2x25x2}{16x3x25x3}\)=\(\dfrac{4}{9}\)
(Chúng ta phải tách \(\dfrac{32x50}{48x75}\) sao cho thuận tiện và đúng)
\(\dfrac{63x81}{135x84}\)= ?
tính theo mẫu:
m:32x50 16x2x25x2 4
_____= _______=
48x75 16x3x25x3 9
63x81
_____=?
135x84
tính nhanh:
a) 32x50/48x75=
b) 63x81/135x84
a)\(\frac{32x50}{48x75}=\frac{2x2}{3x3}=\frac{4}{9}\)
32x50/48x75
=2x4x4x5x2x5/4x3x2x2x5x5x3
=4/3x3=4/9
Tính : Kết quả là một phân số tối giản
a, \(\dfrac{8x4x50}{48x75}\)
b, \(\dfrac{7x9x81}{9x3x5x84}\)
a: \(=\dfrac{32}{48}\cdot\dfrac{50}{75}=\dfrac{2}{3}\cdot\dfrac{2}{3}=\dfrac{4}{9}\)
b: \(=\dfrac{7\cdot9\cdot81}{27\cdot5\cdot84}=\dfrac{9\cdot81}{27\cdot3}\cdot\dfrac{7}{5\cdot28}=9\cdot\dfrac{1}{4\cdot5}=\dfrac{9}{20}\)
\(a,\dfrac{8\times4\times50}{48\times75}=\dfrac{2\times2\times2\times2\times2\times25}{2\times2\times2\times2\times3\times25\times3}=\dfrac{2\times2}{3\times3}=\dfrac{4}{9}\)
\(b,\dfrac{7\times9\times81}{9\times3\times5\times84}=\dfrac{7\times9\times9\times3\times3}{9\times3\times5\times7\times3\times4}=\dfrac{9}{5\times4}=\dfrac{9}{20}\)
b,7×9×819×3×5×84=7×9×9×3×39×3×5×7×3×4=95×4=920
Tính thuận tiện :
M = 3 + \(\dfrac{4}{9}\) x \(\dfrac{7}{25}\) x \(\dfrac{27}{12}\) x \(3\dfrac{4}{7}\) - \(\dfrac{7}{25}\)
Giải giúp e với
\(M=3+\dfrac{4}{9}\times\dfrac{7}{25}\times\dfrac{27}{12}\times3\dfrac{4}{7}-\dfrac{7}{25}\)
\(=3+\dfrac{4}{9}\times\dfrac{7}{25}\times\dfrac{27}{12}\times\dfrac{25}{7}-\dfrac{7}{25}\)
\(=3+\left(\dfrac{4}{9}\times\dfrac{27}{12}\right)\times\left(\dfrac{7}{25}\times\dfrac{25}{7}\right)-\dfrac{7}{25}\)
\(=3+\left(\dfrac{4\times3\times9}{9\times3\times4}\right)\times1-\dfrac{7}{25}\)
\(=3+1\times1-\dfrac{7}{25}\)
\(=3+1-\dfrac{7}{25}\)
\(=4-\dfrac{7}{25}\)
\(=\dfrac{100}{25}-\dfrac{7}{25}\)
\(=\dfrac{93}{25}\)
`3+4/9xx7/25xx27/12xx3 4/7-7/25`
`=3+4/9xx7/25xx27/12xx25/7-7/25`
`=3+7/25xx25/7xx4/9xx27/12-7/25`
`=3+4/9xx9/4xx1-7/25`
`=3+1xx1-7/25`
`=3+1-7/25`
`=75/25+25/25-7/25`
`=93/25`
tính bằng cách thuận tiện\(\dfrac{5}{9}\cdot\dfrac{1}{4}+\dfrac{4}{9}\cdot\dfrac{3}{12}\)
`5/9xx1/4+4/9xx3/12`
`=5/9xx1/4+4/9xx1/4`
`=1/4xx(5/9+4/9)`
`=1/4xx9/9`
`=1/4xx1`
`=1/4`
5/9.1/4+4/9.1/4=(5/9+4/9).1/4=1.1/4=1/4
tính bằng cách thuận tiện nhất a, \(\dfrac{2}{9}\)+\(\dfrac{1}{6}\)+\(\dfrac{3}{5}\) b, \(\dfrac{9}{13}\)+\(\dfrac{4}{13}\)+\(\dfrac{2}{3}\)
a: =20/90+15/90+54/90=89/90
b: =(9/13+4/13)+2/3=1+2/3=5/3
Tính bằng cách thuận tiện.
\(\dfrac{4}{27}+\dfrac{5}{9}+\dfrac{13}{9}-2\)
\(\dfrac{4}{27}+\dfrac{5}{9}+\dfrac{13}{9}-2\\ =\dfrac{4}{27}+\dfrac{18}{9}-2\\ =\dfrac{4}{27}+\dfrac{18\times3}{9\times3}-\dfrac{2\times27}{27}\\ =\dfrac{4}{27}+\dfrac{54}{27}-\dfrac{54}{27}\\ =\dfrac{4}{27}\)
Tính bằng cách thuận tiện nhất:
a)\(\dfrac{1}{5}+\dfrac{5}{9}+\dfrac{4}{5}+\dfrac{1}{9}+\dfrac{3}{9}\)
b)\(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{4}{3}+\dfrac{2}{6}+\dfrac{2}{3}+\dfrac{5}{6}\)
giải giúp mình với !
a, \(=\dfrac{1+4}{5}+\dfrac{5+1+3}{9}=1+1=2\)
b, \(=\dfrac{1+4+2}{3}+\dfrac{1+2+5}{6}=\dfrac{6}{3}+\dfrac{8}{6}=2+\dfrac{4}{3}=\dfrac{6+4}{3}=\dfrac{10}{3}\)
1.tính bằng cách thuận tiện
\(\dfrac{3}{7}\):\(\dfrac{4}{5}\)-\(\dfrac{3}{7}\):\(\dfrac{9}{2}\)
\(=\dfrac{3}{7}\left(\dfrac{5}{4}-\dfrac{2}{9}\right)=\dfrac{3}{7}\cdot\dfrac{45-8}{36}=\dfrac{3}{36}\cdot\dfrac{37}{7}=\dfrac{37}{84}\)
\(\dfrac{3}{7}:\dfrac{4}{5}-\dfrac{3}{7}:\dfrac{9}{2}\)
\(=\dfrac{3}{7}\times\dfrac{5}{4}-\dfrac{3}{7}\times\dfrac{2}{9}\)
\(=\dfrac{3}{7}\times\left(\dfrac{5}{4}-\dfrac{2}{9}\right)\)
\(=\dfrac{3}{7}\times\left(\dfrac{45}{36}-\dfrac{8}{36}\right)\)
\(=\dfrac{3}{7}\times\dfrac{37}{36}\)
\(=\dfrac{37}{84}\)
#DatNe