\(\frac{3}{5}:\frac{7}{3}+\frac{3}{5}:\frac{7}{4}-1\frac{3}{5}\)

\(=\frac{3}{5}.\frac{3}{7}+\frac{3}{5}.\frac{4}{7}-1\frac{3}{5}\)

\(=\frac{3}{5}.\left(\frac{3}{7}+\frac{4}{7}\right)-1\frac{3}{5}\)

\(=\frac{3}{5}.1-1+\frac{3}{5}\)

\(=\frac{3}{5}-\frac{3}{5}-1\)

\(=-1\)

a) 35 :73 +35 :74 −135 

\(=\frac{49}{20}-\frac{8}{5}\) 

= \(\frac{17}{20}\)

\(\frac{3}{5}:\frac{7}{3}+\frac{3}{5}:\frac{7}{4}-1\frac{3}{5}=\frac{3}{5}\times\frac{3}{7}+\frac{3}{5}\times\frac{4}{7}-\frac{8}{5}=\frac{3}{5}\times\left(\frac{3}{7}+\frac{4}{7}\right)-\frac{8}{5}\)

                                                   \(=\frac{3}{5}\times\frac{7}{7}-\frac{8}{5}=\frac{3}{5}-\frac{8}{5}=\frac{3-8}{5}=\frac{-5}{5}=-1\)

=10/3-17/21.7/5(. là nhân đó nha mọi người)

=10/3-17/15

=11/5

\(\frac{10}{3}-\left(6\frac{1}{7}-5\frac{1}{3}\right):\frac{5}{7}\)

\(=\frac{10}{3}-\left(\frac{43}{7}-\frac{16}{3}\right):\frac{5}{7}\)

\(=\frac{10}{3}-\frac{17}{21}:\frac{5}{7}\)

\(=\frac{10}{3}-\frac{17}{15}\)

\(=\frac{50}{15}-\frac{17}{15}=\frac{50-17}{15}=\frac{33}{15}=\frac{11}{5}\)

a)\(\frac{1}{8}.\frac{3}{5} = \frac{{1.3}}{{8.5}} = \frac{3}{{40}}\)           

b)\(\frac{{ - 6}}{7}:\left( { - \frac{5}{3}} \right) = \frac{{ - 6}}{7}.\frac{{ - 3}}{5} = \frac{{18}}{{35}}\)           

c)\(0,6.\left( { - 0,15} \right) = \frac{6}{{10}}.\frac{{ - 15}}{{100}} = \frac{{ - 90}}{{1000}} = \frac{{ - 9}}{{100}}\).

a)\(\frac{{ - 2}}{5} + \frac{3}{7} = \frac{{ - 14}}{{35}} + \frac{{15}}{{35}} = \frac{1}{{35}}\)           

b)\(0,123 - 0,234 =  - \left( {0,234 - 0,123} \right) =  - 0,111.\)

\(\frac{5}{9}-\frac{7}{13}-\frac{5}{9}.\frac{3}{13}+\frac{-5}{9}.\frac{6}{9}\)

= \(\frac{5}{9}-\frac{7}{13}-\frac{5}{3}.\frac{1}{13}+\frac{-5}{3}.\frac{2}{9}\)

=\(\frac{5}{9}-\frac{7}{13}-\frac{5}{39}+\frac{-10}{27}\)

=\(\frac{5}{9}+\frac{-7}{13}+\frac{-5}{39}+\frac{-10}{27}\)

=\(\frac{-13}{27}\)

Chúc bạn học tốt nhea ♥♥♥

\(\frac{5}{9}-\frac{7}{13}-\frac{5}{9}.\frac{3}{13}+\frac{-5}{9}.\frac{61}{9}\)

\(=\frac{5}{9}\left(1-\frac{3}{13}\right)-\frac{7}{13}-\frac{5}{9}.\frac{61}{9}\)

\(=\frac{5}{9}.\frac{10}{13}-\frac{5}{9}.\frac{61}{9}-\frac{7}{13}\)

\(=\frac{5}{9}\left(\frac{10}{13}-\frac{61}{9}\right)-\frac{7}{13}\)\(=-\frac{314}{81}\)

Ori Tinh Nghịch viết nhầm đề bài rồi nha ^^

-377 / 70

a)

i.Ta có: BCNN(12, 30) = 60

60 : 12 = 5; 60 : 30 = 2. Do đó:

\(\frac{5}{{12}} = \frac{{5.5}}{{12.5}} = \frac{{25}}{{60}}\) và \(\frac{7}{{30}} = \frac{{7.2}}{{30.2}} = \frac{{14}}{{60}}.\)

ii.Ta có: BCNN(2, 5, 8) = 40

40 : 2 = 20; 40 : 5 = 8; 40 : 8 = 5. Do đó:

\(\frac{1}{2} = \frac{{1.20}}{{2.20}} = \frac{{20}}{{40}}\)

\(\frac{3}{5} = \frac{{3.8}}{{5.8}} = \frac{{24}}{{40}}\)

\(\frac{5}{8} = \frac{{5.5}}{{8.5}} = \frac{{25}}{{40}}\).

b)

i.Ta có: BCNN(6, 8) = 24

24 : 6 = 4; 24: 8 = 3. Do đó

\(\begin{array}{l}\frac{1}{6} + \frac{5}{8} = \frac{{1.4}}{{6.4}} + \frac{{5.3}}{{8.3}}\\ = \frac{4}{{24}} + \frac{{15}}{{24}} = \frac{{19}}{{24}}.\end{array}\)

ii. Ta có: BCNN(24, 30) = 120

120: 24 = 5; 120: 30 = 4. Do đó:

\(\begin{array}{l}\frac{{11}}{{24}} - \frac{7}{{30}} = \frac{{11.5}}{{24.5}} - \frac{{7.4}}{{30.4}}\\ = \frac{{55}}{{120}} - \frac{{28}}{{120}} = \frac{{27}}{{120}} = \frac{9}{{40}}\end{array}\)

a) Mẫu số chung = BCNN(11, 7) = 77

Thừa số phụ: 77: 11= 7; 77:7 = 11.

Ta có:

\(\begin{array}{l}\frac{7}{{11}} + \frac{5}{7} = \frac{{7.7}}{{11.7}} + \frac{{5.11}}{{7.11}}\\ = \frac{{49}}{{77}} + \frac{{55}}{{77}} = \frac{{104}}{{77}}\end{array}\).

b) Mẫu số chung = BCNN(20, 15)= 60 

Thừa số phụ: 60:20 = 3; 60:15 = 4

Ta có:

\(\begin{array}{l}\frac{7}{{20}} - \frac{2}{{15}} = \frac{{7.3}}{{20.3}} - \frac{{2.4}}{{15.4}}\\ = \frac{{21}}{{60}} - \frac{8}{{60}} = \frac{{13}}{{60}}\end{array}\).