![](https://rs.olm.vn/images/avt/0.png?1311)
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)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: =6/7-5/9
=54/63-35/63
=19/63
b: =1000,02-725,48
=274,54
![](https://rs.olm.vn/images/avt/0.png?1311)
1. Tính
b, 419,23 + 508,79 - 725,48 = 202,54
_học tốt
![](https://rs.olm.vn/images/avt/0.png?1311)
A = \(\frac{1}{5\times6}+\frac{3}{6\times9}+\frac{5}{9\times14}+\frac{7}{14\times21}+\frac{9}{21\times30}\)
A = \(\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{9}+\frac{1}{9}-\frac{1}{14}+\frac{1}{14}-\frac{1}{21}+\frac{1}{21}-\frac{1}{30}\)
A = \(1-\frac{1}{30}\)
A = \(\frac{29}{30}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{5}{6}+\dfrac{3}{2}\cdot\dfrac{4}{5}\)
\(=\dfrac{5}{6}+\dfrac{3\cdot2\cdot2}{2\cdot5}\)
\(=\dfrac{5}{6}+\dfrac{6}{5}\)
\(=\dfrac{61}{30}\)
b) \(\dfrac{6}{7}:\dfrac{9}{14}-1\)
\(=\dfrac{6}{7}\cdot\dfrac{14}{9}-1\)
\(=\dfrac{2\cdot3\cdot7\cdot2}{7\cdot3\cdot3}-1\)
\(=\dfrac{4}{3}-1\)
\(=\dfrac{1}{3}\)
a) \(\dfrac{5}{6}+\dfrac{3}{2}.\dfrac{4}{5}=\dfrac{5}{6}+\dfrac{6}{5}=\dfrac{61}{30}\)
b) \(\dfrac{6}{7}:\dfrac{9}{14}-1=\dfrac{4}{3}-1=\dfrac{1}{3}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
14 : ( 42/ 3 - 15/9 ) + 14 : 2/5 + 8/9
= 14 : ( 42/3 - 5/3 ) + 14 : 2/5 + 8/9
= 14 : 37/3 + 14 : 2/5 + 8/9
= 14 : ( 37/3 + 2/5 ) + 8/9
= 14 : ( 185/15 + 6/15 ) + 8/9
= 14 : 191/15 + 8/9
= 210/15 + 8/9
= 134/9
![](https://rs.olm.vn/images/avt/0.png?1311)
\(14:\left(4\frac{2}{3}-1\frac{5}{9}\right)+14:\left(\frac{2}{3}+\frac{8}{9}\right)\)
\(=14:\frac{28}{9}+14:\frac{3}{4}\)
\(=14\times\left(\frac{9}{28}+\frac{4}{3}\right)\)
\(=14\times\frac{27}{112}=\frac{27}{8}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a)\(\frac{3}{5}x\frac{7}{9}+\frac{11}{9}x\frac{3}{5}-\frac{3}{10}\)
\(=\frac{3}{5}x\left(\frac{7}{9}+\frac{11}{9}\right)-\frac{3}{10}\)
\(=\frac{3}{5}-\frac{3}{10}\)
\(=\frac{3}{5}\)
tương tự cho phần b nhé
chúc học tốt
=
a.\(\frac{9}{10}\)
b.\(\frac{20}{13}\)
cho mình nha, mình không có thời gian để giải công thức nên mình viết được chừng này thôi ^ ^
![](https://rs.olm.vn/images/avt/0.png?1311)
\(5-\frac{3}{7}.\frac{14}{9}\)
\(=5-\frac{3.2}{1.9}\)
\(=5-\frac{2}{3}\)
\(=\frac{15}{3}-\frac{2}{3}=\frac{13}{3}\)
\(5-\frac{3}{7}.\frac{14}{9}\) \(\frac{5}{6}:\left(\frac{4}{5}+2\right)\) \(\frac{11}{9}:\frac{16}{9}.4\)
\(=5-\frac{2}{3}\) \(=\frac{5}{6}:\frac{14}{5}\) \(=\frac{11}{16}.4\)
\(=\frac{13}{3}\) \(=\frac{25}{84}\) \(=\frac{11}{4}\)