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F
23 tháng 1 2020
Bài giải
a, \(\frac{4}{5}-\frac{2}{3}+\frac{1}{5}-\frac{1}{3}\)
\(=\left(\frac{4}{5}+\frac{1}{5}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)=1-1=0\)
b, \(\frac{2}{5}\text{ x }\frac{7}{4}-\frac{2}{5}\text{ x }\frac{3}{7}\)
\(=\frac{2}{5}\text{ x }\left(\frac{7}{4}-\frac{3}{7}\right)=\frac{2}{5}\text{ x }\frac{37}{28}=\frac{37}{70}\)
c, \(\frac{13}{4}\text{ x }\frac{2}{3}\text{ x }\frac{4}{13}\text{ x }\frac{3}{12}=\frac{13\text{ x }2\text{ x }4\text{ x }3}{4\text{ x }3\text{ x }13\text{ x }12}=\frac{1}{6}\)
d, \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)
\(=1+1+1\)
\(=3\)
e, \(\frac{2}{5}+\frac{6}{9}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{2}{5}+\frac{2}{3}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{1}{5}\left(2+3\right)+\frac{1}{3}\left(2+1\right)+\frac{1}{4}\left(3+1\right)\)
\(=\frac{1}{5}\cdot5+\frac{1}{3}\cdot3+\frac{1}{4}\cdot4\)
\(=1+1+1\)
\(=3\)
M
23 tháng 1 2020
a, \(\frac{4}{5}-\frac{2}{3}+\frac{1}{5}-\frac{1}{3}\)
\(=\left(\frac{4}{5}+\frac{1}{5}\right)-\left(\frac{2}{3}+\frac{1}{3}\right)=1-1=0\)
b, \(\frac{2}{5}\text{ x }\frac{7}{4}-\frac{2}{5}\text{ x }\frac{3}{7}\)
\(=\frac{2}{5}\text{ x }\left(\frac{7}{4}-\frac{3}{7}\right)=\frac{2}{5}\text{ x }\frac{37}{28}=\frac{37}{70}\)
c, \(\frac{13}{4}\text{ x }\frac{2}{3}\text{ x }\frac{4}{13}\text{ x }\frac{3}{12}=\frac{13\text{ x }2\text{ x }4\text{ x }3}{4\text{ x }3\text{ x }13\text{ x }12}=\frac{1}{6}\)
d, \(\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{18}{21}+\frac{3}{21}\right)+\left(\frac{19}{32}+\frac{13}{32}\right)\)
\(=1+1+1\)
\(=3\)
e, \(\frac{2}{5}+\frac{6}{9}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{2}{5}+\frac{2}{3}+\frac{3}{4}+\frac{3}{5}+\frac{1}{3}+\frac{1}{4}\)
\(=\frac{1}{5}\left(2+3\right)+\frac{1}{3}\left(2+1\right)+\frac{1}{4}\left(3+1\right)\)
\(=\frac{1}{5}\cdot5+\frac{1}{3}\cdot3+\frac{1}{4}\cdot4\)
\(=1+1+1\)
\(=3\)
TT
1
26 tháng 3 2019
\(\frac{2}{5}\times\frac{3}{8}+\frac{3}{4}=\frac{2\times3}{5\times8}+\frac{3}{4}=\frac{1\times3}{5\times4}+\frac{3}{4}=\frac{3}{20}+\frac{3}{4}=\frac{3}{20}+\frac{15}{20}=\frac{18}{20}=\frac{9}{10}\)
\(\frac{2}{5}+\frac{3}{8}\times\frac{3}{4}=\frac{2}{5}+\frac{9}{32}=\frac{64}{160}+\frac{45}{160}=\frac{109}{160}\)
Hai bài kia tương tự
27 tháng 3 2022
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
27 tháng 3 2022
có thể tính nốt phép tính 3/4 x 3/2 + 3/4 x 1/2 có đc ko ạ
HT
5
5 tháng 5 2017
\(\frac{1}{2}\)x \(\frac{2}{3}\)= \(\frac{1\times2}{2\times3}\)= \(\frac{2}{6}\)= \(\frac{1}{3}\)
\(\frac{4}{5}\): \(\frac{2}{4}\)= \(\frac{4}{5}\)x \(2\)= \(\frac{8}{5}\)
\(\frac{9}{8}\)+ \(\frac{1}{4}\)= \(\frac{36}{32}\)+ \(\frac{8}{32}\)= \(\frac{44}{32}\)= \(\frac{11}{8}\)
\(\frac{7}{4}\)- \(\frac{2}{4}\)= \(\frac{7-2}{4}\)= \(\frac{5}{4}\)
BD
4
17 tháng 3 2018
7/8 + 3/4=13/8
3/2 + 4/5=23/10
6/7 * 5/6=5/7
5/6 : 8/9=15/16
17 tháng 3 2018
\(\frac{7}{8}+\frac{3}{4}=\frac{28}{32}+\frac{24}{32}=\frac{52}{32}\)
\(\frac{3}{2}+\frac{4}{5}=\frac{15}{10}+\frac{8}{10}=\frac{23}{10}\)
\(\frac{6}{7}x\frac{5}{6}=\frac{30}{42}\)
\(\frac{5}{6}:\frac{8}{9}=\frac{5}{6}x\frac{9}{8}=\frac{45}{48}\)
25 tháng 5 2021
a)3/4 x 2/9 + 1/3
=1/6 + 1/3
=1/6 + 2/6
=1/2
b)5/4:2.9+1/2
=1.25 : 2.9 + 1/2
=25/58 + 1/2 =27/29
c)7/2 - 1/4 x 1/5
=7/2 - 1/20
=69/20
d)5/4+1/5:2/3
=5/4 + 3/10
=31/20
Học tốt!
23 tháng 3 2022
mk ko viết đề nha:
a)=(1/2+1/2)+ (1/3+2/3)+(1/4 +3/4)+(1/5+4/5)
=(2/2 + 3/3) + (4/4 + 5/5)
=2/2 + 4/2
=6/4
À mik lm đc câu a thui nha!Nhưng k cho mik vs nhé!
Lời giải:
$\frac{9}{4}\times \frac{2}{5}+\frac{3}{4}\times \frac{3}{5}+\frac{1}{5}\times 3:\frac{3}{4}$
$=\frac{9}{10}+\frac{9}{20}+\frac{3}{5}\times \frac{4}{3}$
$=\frac{18}{20}+\frac{9}{20}+\frac{4}{5}$
$=\frac{18}{20}+\frac{9}{20}+\frac{16}{20}$
$=\frac{18+9+16}{20}=\frac{43}{20}$
9/4 x 2/5 + 3/4 x 3/5 + 1/5 x 3 : 3/4
= 9/10 + 9/20 + 3/5 x 4/3
= 18/20 + 9/20 + 16/20
= 43/20