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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
2/3 : 1/2 + 1/3 : 1/2
= 4/3 + 2/3
= 2
3/5 : 4/7 : 7/6
= 21/20 : 7/6
= 9/10
4/9 x 7/5 : 7/9
= 28/45 : 7/9
= 4/5
Em nhớ k anh nha
có thể tính nốt phép tính 3/4 x 3/2 + 3/4 x 1/2 có đc ko ạ
1.
\(\frac{5}{3}-\frac{1}{4}+\frac{1}{3}-\frac{3}{4}\)
\(=\left(\frac{5}{3}+\frac{1}{3}\right)-\left(\frac{1}{4}+\frac{3}{4}\right)\)
\(=2-1=1\)
\(\frac{2}{7}\cdot\frac{1}{5}+\frac{2}{7}\cdot\frac{4}{5}=\frac{2}{7}\cdot\left(\frac{1}{5}+\frac{4}{5}\right)=\frac{2}{7}\cdot1=\frac{2}{7}\)
#Louis
\(1.a)\frac{5}{3}-\frac{1}{4}+\frac{1}{3}-\frac{3}{4}\)
\(=\left(\frac{5}{3}+\frac{1}{3}\right)-\left(\frac{1}{4}+\frac{3}{4}\right)\)
\(=2-1\)
\(=1\)
\(b)\frac{2}{7}\times\frac{1}{5}+\frac{2}{7}\times\frac{4}{5}\)
\(=\frac{2}{7}\times\left(\frac{1}{5}+\frac{4}{5}\right)\)
\(=\frac{2}{7}\times1\)
\(=\frac{2}{7}\)
\(2.a)\frac{5}{6}+\frac{7}{12}-\frac{2}{9}\)
\(=\frac{30}{36}+\frac{21}{36}-\frac{8}{36}\)
\(=\frac{43}{36}\)
\(b)\frac{4}{9}\times\frac{5}{8}+\frac{1}{6}\)
\(=\frac{5}{18}+\frac{1}{6}=\frac{5}{18}+\frac{3}{18}\)
\(=\frac{8}{18}=\frac{4}{9}\)
\(c)2:\frac{3}{11}-\frac{13}{12}\)
\(=2\times\frac{11}{3}-\frac{13}{12}\)
\(=\frac{22}{3}-\frac{13}{12}\)
\(=\frac{25}{4}\)
1) 1/5 . 5/4 + 1/5 . 5/4
= (1/5 + 1/5) . 5/4
= 1/5 . 5/4
= 1/4
2)tự làm
1.\(\frac{1}{5}\times\frac{5}{4}+\frac{1}{5}\times\frac{5}{4}\)
\(=\frac{1}{5}\times\frac{5}{4}\times2\)
\(=\frac{1\times5\times2}{5\times4}\)
\(=\frac{1}{2}\)
2.\(\frac{7}{6}\times\frac{2}{5}-\frac{1}{3}\times\frac{2}{5}+\frac{5}{6}\times\frac{2}{5}\)
\(=\frac{2}{5}\times\left(\frac{7}{6}-\frac{1}{3}+\frac{5}{6}\right)\)
\(=\frac{2}{5}\times\left(\frac{7}{6}-\frac{2}{6}+\frac{5}{6}\right)\)
\(=\frac{2}{5}\times\frac{5}{3}\)
\(=\frac{2}{3}\)
a) \(\frac{3}{4}\times\frac{1}{2}\times2\)
C1: \(=\frac{3}{8}\times2=\frac{3}{4}\)
C2: \(=\frac{3}{4}\times1=\frac{3}{4}\)
b) \(\left[\frac{3}{4}+\frac{1}{2}\right]\times\frac{5}{7}\)
C1: \(=\frac{5}{4}\times\frac{5}{7}=\frac{25}{28}\)
C2: \(=\frac{3}{4}\times\frac{5}{7}+\frac{1}{2}\times\frac{5}{7}=\frac{15}{28}+\frac{5}{14}=\frac{25}{28}\)
a/\(\frac{3}{4}\cdot\frac{1}{2}\cdot2=\frac{6}{8}\cdot2=\frac{12}{8}=\frac{3}{2}\)
\(\frac{3}{4}\cdot\frac{1}{2}\cdot2=\frac{3}{4}\cdot\frac{2}{2}=\frac{3}{4}\cdot1=\frac{3}{4}\)
b/\(\left(\frac{3}{4}+\frac{1}{2}\right)\cdot\frac{5}{7}=\frac{5}{4}\cdot\frac{5}{7}=\frac{25}{28}\)
\(\left(\frac{3}{4}+\frac{1}{2}\right)\cdot\frac{5}{7}=\frac{3}{4}\cdot\frac{5}{7}+\frac{1}{2}\cdot\frac{5}{7}=\frac{15}{28}+\frac{5}{14}=\frac{15}{28}+\frac{10}{28}=\frac{25}{28}\)
c/\(\frac{5}{7}\cdot\frac{13}{21}+\frac{2}{7}\cdot\frac{13}{21}=\frac{65}{147}+\frac{26}{147}=\frac{91}{147}=\frac{13}{21}\)
\(\frac{5}{7}\cdot\frac{13}{21}+\frac{2}{7}\cdot\frac{13}{21}=\left(\frac{5}{7}+\frac{2}{7}\right)\cdot\frac{13}{21}=1\cdot\frac{13}{21}=\frac{13}{21}\)
Học tốt @#_#@
1) \(=\left(\frac{3}{5}+\frac{2}{5}\right).\frac{6}{11}\)
\(=1.\frac{6}{11}\)
\(=\frac{6}{11}\)
2)\(\frac{17}{25}.\left(\frac{11}{19}+\frac{6}{19}+\frac{2}{19}\right)\)
\(=\frac{17}{25}.1\)
\(=\frac{17}{25}\)
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
= \(\frac{3}{4}\)
(2/3 x 4/5) x 5/6
= 8/15 x 5/6
= 4/9
(2/3 x 4/5) x 5/6
= (5/6 x 4/5) x 2/3
= 2/3 x 2/3
= 4/9
(1/2 + 1/3) x 1/5
= 5/6 x 1/5
= 1/6
(1/2 + 1/3) x 1/5
= (1/2 x 1/5) + (1/3 x 1/5)
= 1/10 + 1/15
= 1/6
4A6?
\(=\left(\dfrac{3+8}{12}\right)\cdot\dfrac{4}{5}=\dfrac{11}{12}\cdot\dfrac{4}{5}=\dfrac{44}{60}=\dfrac{11}{15}\)