Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{21}{15}\) + \(\dfrac{2}{5}\) = \(\dfrac{9}{5}\)
b) \(\dfrac{6}{16}\) + \(\dfrac{1}{8}\) = \(\dfrac{1}{2}\)
c) \(\dfrac{3}{12}\) + \(\dfrac{3}{4}\) = 1
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{15}{25}=\dfrac{15:5}{25:5}=\dfrac{3}{5}\\ \dfrac{24}{28}=\dfrac{24:4}{28:4}=\dfrac{6}{7}\\ \dfrac{18}{33}=\dfrac{18:3}{33:3}=\dfrac{6}{11}\\ \dfrac{12}{36}=\dfrac{12:12}{36:12}=\dfrac{1}{3}.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{4}{24}+\dfrac{7}{6}=\dfrac{4}{24}+\dfrac{28}{24}=\dfrac{4+28}{24}=\dfrac{32}{24}=\dfrac{4}{3}\)
b) \(\dfrac{10}{15}-\dfrac{1}{3}=\dfrac{10}{15}-\dfrac{5}{15}=\dfrac{10-5}{15}=\dfrac{5}{15}=\dfrac{1}{3}\)
c) \(\dfrac{21}{28}-\dfrac{1}{4}=\dfrac{21}{28}-\dfrac{7}{28}=\dfrac{21-7}{28}=\dfrac{14}{28}=\dfrac{1}{2}\)
d) \(\dfrac{35}{40}+\dfrac{5}{8}=\dfrac{35}{40}+\dfrac{25}{40}=\dfrac{35+25}{40}=\dfrac{60}{40}=\dfrac{3}{2}\)
\(a)\dfrac{4}{24}=\dfrac{1}{6} \\ \dfrac{1}{6}+\dfrac{7}{6}\\ =\dfrac{8}{6}=\dfrac{4}{3}\\ b)\dfrac{10}{15}=\dfrac{2}{3}-\dfrac{1}{3}\\ =\dfrac{1}{3}\\ c)\dfrac{21}{28}=\dfrac{3}{4}\\ \dfrac{3}{4}-\dfrac{1}{4}\\ =\dfrac{2}{4}=\dfrac{1}{2}\\ d)\dfrac{35}{40}=\dfrac{7}{8}\\ \dfrac{7}{8}+\dfrac{5}{8}\\ =\dfrac{12}{8}=\dfrac{3}{2}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(=\dfrac{5}{3}+2-\dfrac{3}{4}=\dfrac{5.4+2.12-3.3}{12}=\dfrac{20+24-9}{12}=\dfrac{35}{12}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: \(\dfrac{3}{9}\times\dfrac{5}{4}=\dfrac{5}{4}\times\dfrac{1}{3}=\dfrac{5\times1}{4\times3}=\dfrac{5}{12}\)
b: \(\dfrac{10}{15}\times\dfrac{3}{5}=\dfrac{3}{5}\times\dfrac{2}{3}=\dfrac{3\times2}{5\times3}=\dfrac{2}{5}\)
c: \(\dfrac{5}{8}\times\dfrac{4}{12}=\dfrac{5}{8}\times\dfrac{1}{3}=\dfrac{5}{3\times8}=\dfrac{5}{24}\)
d: \(\dfrac{9}{27}\times\dfrac{3}{21}=\dfrac{1}{7}\times\dfrac{1}{3}=\dfrac{1\times1}{7\times3}=\dfrac{1}{21}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{25}{60}+6\times\dfrac{1}{8}=\dfrac{25}{60}+\dfrac{3}{4}=\dfrac{25}{69}+\dfrac{45}{60}=\dfrac{25+45}{60}=\dfrac{70}{60}=\dfrac{7}{6}\)
b) \(\dfrac{15}{9}\times\left(6:\dfrac{30}{9}\right)=\dfrac{15}{9}\times\left(6\times\dfrac{30}{9}\right)=\dfrac{15}{9}\times20=\dfrac{100}{3}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{2}{5}-\dfrac{3}{15}\)
\(=\dfrac{2}{5}-\dfrac{3:3}{15:3}\)
\(=\dfrac{2}{5}-\dfrac{1}{5}\)
\(=\dfrac{1}{5}\)
b) \(\dfrac{9}{27}-\dfrac{2}{9}\)
\(=\dfrac{9:3}{27:3}-\dfrac{2}{9}\)
\(=\dfrac{3}{9}-\dfrac{2}{9}\)
\(=\dfrac{1}{9}\)
c) \(\dfrac{18}{24}-\dfrac{4}{8}\)
\(=\dfrac{18:6}{24:6}-\dfrac{4:2}{8:2}\)
\(=\dfrac{3}{4}-\dfrac{2}{4}\)
\(=\dfrac{1}{4}\)
d) \(\dfrac{6}{16}-\dfrac{10}{64}\)
\(=\dfrac{6\times2}{16\times2}-\dfrac{10:2}{64:2}\)
\(=\dfrac{12}{32}-\dfrac{5}{32}\)
\(=\dfrac{7}{32}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{25}{30}=\dfrac{5}{6}\)
\(\dfrac{9}{15}=\dfrac{3}{5}\)
\(\dfrac{10}{12}=\dfrac{5}{6}\)
\(\dfrac{6}{10}=\dfrac{3}{5}\)
Bạn nhìn theo phần rút gọn tui gửi mà so sánh các phân số khác nhek
a, 15/25 - 3/21 = 3/5 - 1/7 = 21/35 - 5/35 = 18/35
b, 24/36 - 6/12 = 2/3 - 1/2 = 4/6 - 3/6 = 1/6
a)15/25-3/21=3/5-1/7=16/35 b)24/36-6/12=2/3-1/2=1/6