TÍNH BẰNG HAI CÁCH : [1/2 + 1/3 ] x 2 / 5
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a) Cách 1 : (3/4 + 1/2) x 5/7
= 5/4 x 5/7
= 25/28
Cách 2 : (3/4 + 1/2) x 5/7
= 3/4 x 5/7 + 1/2 x 5/7
= 15/28 + 5/14
= 25/28
b) Cách 1 : 5/7 x 13/21 + 2/7 x 13/21
= 65/147 + 26/147
= 13/21
Cách 2 : 5/7 x 13/21 + 2/7 x 13/21
= (5/7 + 2/7) x 13/21
= 1 x 13/21
= 13/21
câu c tự làm
`(1/3 + 1/5) xx 1/4`
`= ( 5/15 + 3/15) xx 1/4`
`= 8/15 xx 1/4`
`= 8/60`
`= 2/15`
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`(1/3 + 1/5) xx 1/4`
`= 1/3 xx 1/4 + 1/5 xx 1/4`
`= 1/12 +1/20`
`=2/15`
\(C_1:\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{4}\times\dfrac{1}{3}+\dfrac{1}{4}\times\dfrac{1}{5}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{2}{15}\)
\(C_2:\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8\times1}{15\times4}=\dfrac{8}{60}=\dfrac{2}{15}\)
\(a,\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8}{60}=\dfrac{2}{15}\)
\(\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{3}\times\dfrac{1}{4}+\dfrac{1}{5}\times\dfrac{1}{4}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{20}{240}+\dfrac{12}{240}=\dfrac{32}{240}=\dfrac{2}{15}\)
\(b,\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{2}{5}\times\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\times1=\dfrac{2}{5}\)
\(\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{6}{35}+\dfrac{8}{35}=\dfrac{14}{35}=\dfrac{2}{5}\)
trả lời nhanh nha! trả lời trong tối hôm nay 19/3/2023 ạ
a: \(=\dfrac{3}{22}\cdot22\cdot\dfrac{3}{11}=3\cdot\dfrac{3}{11}=\dfrac{9}{11}\)
b: \(=\dfrac{5}{6}\cdot\dfrac{2}{5}=\dfrac{1}{3}\)
c: \(=\dfrac{17}{21}\left(\dfrac{3}{5}+\dfrac{2}{5}\right)=\dfrac{17}{21}\)
\(=\dfrac{14+15}{18}\cdot\dfrac{3}{5}=\dfrac{29}{18}\cdot\dfrac{3}{5}=\dfrac{29}{30}\)
a) Cách 1
\(\frac{3}{4}\)x \(\frac{1}{2}\)x \(2\)
= \(\frac{3}{8}\)x \(2\)
= \(\frac{3}{4}\)
Cách 2
\(\frac{3}{4}\)x \(\frac{1}{2}\)x \(2\)
= \(\frac{3}{4}\)x \(\left(\frac{1}{2}x2\right)\)
= \(\frac{3}{4}\)x 1
= \(\frac{3}{4}\)
1/4*1/2+1/6*1/2=1/8+1/12=20/96 C2 ( 1/4+1/6)*1/2
=10/24*1/2=10/48
b,(3/2-2/5)*1/3=11/10*1/3 C2 3/2*1/3+2/5*1/3
=3/6+2/15= 53/90
=11/30
\(\left(\frac{1}{4}+\frac{1}{6}\right)x\frac{1}{2}\) \(\left(\frac{3}{2}-\frac{2}{5}\right)x\frac{1}{3}\)
\(c1:=\frac{5}{12}x\frac{1}{2}=\frac{5}{24}\) \(c1:\frac{11}{10}x\frac{1}{3}=\frac{11}{30}\)
\(c2:=\frac{1}{4}x\frac{1}{2}+\frac{1}{6}x\frac{1}{2}\) \(c2:\frac{3}{2}x\frac{1}{3}-\frac{2}{5}x\frac{1}{3}\)
\(=\frac{1}{8}+\frac{1}{12}=\frac{12}{96}+\frac{8}{96}=\frac{20}{96}=\frac{5}{24}\) \(=\frac{1}{2}-\frac{2}{15}=\frac{11}{30}\)
CHÚC BẠN HỌC GIỎI
\(\left(\frac{1}{2}+\frac{1}{3}\right)\times\frac{2}{5}\)
\(C1:\frac{5}{6}\times\frac{2}{5}=\frac{1}{3}\)
\(C2:\frac{1}{2}\times\frac{2}{5}+\frac{1}{3}\times\frac{2}{5}=\frac{1}{5}+\frac{2}{15}=\frac{1}{3}\)
c1:=5/6 x 2/5
=1/3
c2:=1/2 x 2/5+1/3 x 2/5
=1/5+3/10
=5/15
=1/3
**** cho mình nha