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![](https://rs.olm.vn/images/avt/0.png?1311)
a) $\frac{1}{6}:\frac{3}{7} = \frac{1}{6} \times \frac{7}{3} = \frac{7}{{18}}$
b) $\frac{5}{{12}}:\frac{1}{4} = \frac{5}{{12}} \times \frac{4}{1} = \frac{{5 \times 4}}{{12 \times 1}} = \frac{{5 \times 4}}{{4 \times 3 \times 1}} = \frac{5}{3}$
c) $\frac{4}{{15}}:\frac{8}{3} = \frac{4}{{15}} \times \frac{3}{8} = \frac{{4 \times 3}}{{15 \times 8}} = \frac{{4 \times 3}}{{5 \times 3 \times 4 \times 2}} = \frac{1}{{10}}$
d) $\frac{{18}}{5}:\frac{9}{{10}} = \frac{{18}}{5} \times \frac{{10}}{9} = \frac{{18 \times 10}}{{5 \times 9}} = \frac{{9 \times 2 \times 5 \times 2}}{{5 \times 9}} = 4$
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\frac{2}{5}+\frac{9}{15}=\frac{2}{5}+\frac{3}{5}=\frac{5}{5}=1\)
b) \(\frac{15}{45}+\frac{25}{30}=\frac{1}{3}+\frac{5}{6}=\frac{2}{6}+\frac{5}{6}=\frac{7}{6}\)
c) \(\frac{28}{32}+\frac{45}{72}=\frac{7}{8}+\frac{5}{8}=\frac{12}{8}=\frac{3}{2}\)
d) \(\frac{8}{28}+\frac{5}{30}=\frac{2}{7}+\frac{1}{6}=\frac{12}{42}+\frac{7}{42}=\frac{19}{42}\)
a) \(\frac{2}{5}+\frac{9}{15}\)=\(\frac{2}{5}+\frac{3}{5}=\frac{2+3}{5}=1\)
b)\(\frac{15}{45}+\frac{25}{30}=\frac{1}{3}+\frac{5}{6}=\frac{2}{6}+\frac{5}{6}=\frac{2+5}{6}=\frac{7}{6}\)
c)\(\frac{28}{32}+\frac{45}{72}=\frac{7}{8}+\frac{5}{8}=\frac{7+5}{8}=\frac{12}{8}=\frac{3}{2}\)
d)\(\frac{8}{28}+\frac{5}{30}=\frac{2}{7}+\frac{1}{6}=\frac{12}{42}+\frac{7}{42}=\frac{12+7}{42}=\frac{19}{42}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
1.
a) \(\frac{16}{24}-\frac{1}{3}=\frac{16}{24}-\frac{8}{24}=\)\(\frac{8}{24}=\frac{1}{3}\)
b) \(\frac{4}{5}-\frac{12}{60}=\frac{48}{60}-\frac{12}{60}=\frac{36}{60}=\frac{9}{15}\)
3.
a)\(\frac{17}{6}-\frac{2}{6}=\frac{17-2}{6}=\frac{15}{6}\)
b) \(\frac{16}{15}-\frac{11}{15}=\frac{16-11}{15}=\frac{5}{15}=\frac{1}{3}\)
c) \(\frac{19}{12}-\frac{13}{12}=\frac{19-13}{12}=\frac{6}{12}=\frac{1}{2}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Rút gọn:
\(\frac{18}{30}=\frac{18:6}{30:6}=\frac{3}{5}\)
\(\frac{36}{27}=\frac{36:9}{27:9}=\frac{4}{3}\)
\(\frac{64}{80}=\frac{64:16}{80:16}=\frac{4}{5}\)
\(\frac{45}{35}=\frac{45:5}{35:5}=\frac{9}{7}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Các phân số tối giản:
\(\frac{1}{5}\text{ };\text{ }\frac{17}{20}\)
b) Rút gọn:
\(\frac{12}{18}=\frac{12\div6}{18\div6}=\frac{2}{3}\)
\(\frac{15}{95}=\frac{15\div5}{95\div5}=\frac{3}{19}\)
a) \(\frac{1}{5}\);\(\frac{17}{20}\)
b) \(\frac{12}{18}\)= \(\frac{2}{3}\);\(\frac{15}{95}\)= \(\frac{3}{19}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1:
a: 6/9=2/3
6/24=1/4
48/96=1/2
42/98=3/7
b: 24/36=2/3
18/30=3/5
15/120=1/8
80/240=1/3
c: 5/25=1/5
75/100=3/4
64/720=4/45
16/1000=2/125
Bài 2:
Các phân số bằng 2/3 là 34/51; 20/30; 84/126
Bài 1 :
a) 6/9 = 2/3 ; 6/24 = 1/4 ; 48/96 = 1/2 ; 42/98 = 3/7
b) 24/36 = 2/3 ; 18/30 = 3/5 ; 15/120 = 1/8 ; 80 / 240 = 1/3
c) 5 / 25 = 1/5 ; 75/100=3/4 ; 64/720=4/45 ; 16/1000=2/125
Bài 2 :
Các phân số bằng 2/3 là :
\(\text{34/51; 20/30; 84/126}\)
\(a,\frac{15}{18}=\frac{5}{6}\)
\(b,\frac{144}{351}=\frac{16}{39}\)
\(c,\frac{6}{30}=\frac{1}{5}\)
\(d,\frac{2005}{3000}=\frac{401}{600}\)
a) \(\frac{15}{18}=\frac{5}{6}\)
b) \(\frac{144}{351}=\frac{16}{39}\)
c) \(\frac{6}{30}=\frac{1}{5}\)
d) \(\frac{2005}{3000}=\frac{401}{600}\)