giúp mik với ạ!!!

1C sai \(\dfrac{9}{27}=\dfrac{1}{3}\) mới đúng

2. Em ghi thiếu 2 phân số cần quy đồng

3.C

4.D

Bài 2:

a: \(\dfrac{1}{4};\dfrac{2}{5}\)

\(\dfrac{1}{4}=\dfrac{1\cdot5}{4\cdot5}=\dfrac{5}{20}\)

\(\dfrac{2}{5}=\dfrac{2\cdot4}{5\cdot4}=\dfrac{8}{20}\)

\(\dfrac{2}{3};\dfrac{7}{8}\)

\(\dfrac{2}{3}=\dfrac{2\cdot8}{3\cdot8}=\dfrac{16}{24}\)

\(\dfrac{7}{8}=\dfrac{7\cdot3}{8\cdot3}=\dfrac{21}{24}\)

\(\dfrac{3}{4};\dfrac{5}{6}\)

\(\dfrac{3}{4}=\dfrac{3\cdot3}{4\cdot3}=\dfrac{9}{12}\)

\(\dfrac{5}{6}=\dfrac{5\cdot2}{6\cdot2}=\dfrac{10}{12}\)

b: \(\dfrac{1}{3};\dfrac{7}{9}\)

\(\dfrac{1}{3}=\dfrac{1\cdot3}{3\cdot3}=\dfrac{3}{9}\)

\(\dfrac{7}{9}=\dfrac{7\cdot1}{9\cdot1}=\dfrac{7}{9}\)

\(\dfrac{3}{4};\dfrac{9}{24}\)

\(\dfrac{3}{4}=\dfrac{3\cdot6}{4\cdot6}=\dfrac{18}{24}\)

\(\dfrac{9}{24}=\dfrac{9\cdot1}{24\cdot1}=\dfrac{9}{24}\)

\(\dfrac{7}{10};\dfrac{19}{30}\)

\(\dfrac{7}{10}=\dfrac{7\cdot3}{10\cdot3}=\dfrac{21}{30}\)

\(\dfrac{19}{30}=\dfrac{19\cdot1}{30\cdot1}=\dfrac{19}{30}\)

Bài 1:

\(\dfrac{36}{108}=\dfrac{36:36}{108:36}=\dfrac{1}{3}\)

\(\dfrac{28}{30}=\dfrac{28:2}{30:2}=\dfrac{14}{15}\)

\(\dfrac{42}{98}=\dfrac{42:14}{98:14}=\dfrac{3}{7}\)

\(\dfrac{15}{120}=\dfrac{15:15}{120:15}=\dfrac{1}{8}\)

\(\dfrac{84}{364}=\dfrac{84:28}{364:28}=\dfrac{3}{13}\)

\(\dfrac{120}{100}=\dfrac{120:20}{100:20}=\dfrac{6}{5}\)

\(\dfrac{418}{38}=\dfrac{418:38}{38:38}=\dfrac{11}{1}=11\)

\(\dfrac{96}{1056}=\dfrac{96:96}{1056:96}=\dfrac{1}{11}\)

\(\dfrac{3838}{4040}=\dfrac{3838:101}{4040:101}=\dfrac{38}{40}=\dfrac{38:2}{40:2}=\dfrac{19}{20}\)

\(\dfrac{119119}{123123}=\dfrac{119119:1001}{123123:1001}=\dfrac{119}{123}\)

help! giúp mik với ạ!!!

2. B
3. A

1-5/6=1/6

1-2/7=5/7

1/6 <2/6< 5/7

vậy 5/6 <2/7

ko chắc chắn, đúng k mk nhé

a: \(\dfrac{15}{90}=\dfrac{15:3}{90:3}=\dfrac{5}{30}=\dfrac{5:5}{30:5}=\dfrac{1}{6}\)

b: \(\dfrac{15}{90}=\dfrac{15\cdot2}{90\cdot2}=\dfrac{30}{180}\)

\(\dfrac{15}{90}=\dfrac{15\cdot3}{90\cdot3}=\dfrac{45}{270}\)

\(\dfrac{15}{90}=\dfrac{15\cdot4}{90\cdot4}=\dfrac{60}{360}\)

\(\dfrac{15}{90}=\dfrac{15\cdot5}{90\cdot5}=\dfrac{75}{450}\)

\(\dfrac{15}{90}=\dfrac{15\cdot6}{90\cdot6}=\dfrac{90}{540}\)

Mình không biết

Hihi!

\(\frac{2}{5}\)và \(\frac{3}{2}\):

\(\frac{2}{5}=\frac{2\times2}{5\times2}=\frac{4}{10};\frac{3}{2}=\frac{3\times5}{2\times5}=\frac{15}{10}\)

\(\frac{7}{5}\)và \(\frac{1}{6}\):

\(\frac{7}{5}=\frac{7\times6}{5\times6}=\frac{42}{30};\frac{1}{6}=\frac{1\times5}{6\times5}=\frac{5}{30}\)

\(\frac{2}{5}=\frac{4}{10}\);     \(\frac{3}{2}=\frac{15}{10}\)

\(\frac{7}{5}=\frac{42}{30}\);   \(\frac{1}{6}=\frac{5}{30}\)

\(\frac{4}{3}=\frac{8}{6}\);   \(\frac{7}{2}=\frac{21}{6}\)

\(\frac{3}{4}=\frac{15}{20}\);   \(\frac{2}{5}=\frac{8}{20}\)

\(\frac{4}{3}\)và \(\frac{7}{2}\):

\(\frac{4}{3}=\frac{4\times2}{3\times2}=\frac{8}{6};\frac{7}{2}=\frac{7\times3}{2\times3}=\frac{21}{6}\)

\(\frac{3}{4}\)và \(\frac{2}{5}\):

\(\frac{3}{4}=\frac{3\times5}{4\times5}=\frac{15}{20};\frac{2}{5}=\frac{2\times4}{5\times4}=\frac{8}{20}\)

a) 36/45 và 35/45

b)8/12 và 5/12

k nha

a) \(\frac{4}{5}\) và \(\frac{7}{9}\)

Mẫu số chung: \(45\)

Ta có: \(\frac{4}{5}=\frac{4\cdot9}{5\cdot9}=\frac{36}{45}\)

\(\frac{7}{9}=\frac{7\cdot5}{9\cdot5}=\frac{35}{45}\)

Vậy QĐMS các p/s \(\frac{4}{5};\frac{7}{9}\) ta đc \(\frac{36}{45};\frac{35}{45}\)

b) \(\frac{2}{3}\) và \(\frac{5}{12}\)

Mẫu số chung: \(12\)  

Ta có: \(\frac{2}{3}=\frac{2\cdot4}{3\cdot4}=\frac{8}{12}\)

\(\frac{5}{12}\) giữ nguyên

Vậy QĐMS các p/s \(\frac{2}{3};\frac{5}{12}\) ta đc \(\frac{8}{12};\frac{5}{12}\)

A.\(\frac{4}{5}\)và\(\frac{7}{9}\);Mẫu số chung:45

\(\frac{4}{5}=\frac{4\times9}{5\times9}=\frac{36}{45};\frac{7}{9}=\frac{7\times5}{9\times5}=\frac{35}{45}\)

B.\(\frac{2}{3}\)và\(\frac{5}{12}\);Mẫu số chung:12

\(\frac{2}{3}=\frac{2\times4}{3\times4}=\frac{8}{12}\)và giữ nguyên phân số\(\frac{5}{12}\)

MSC:60 NHA BẠN 

ko bé ơi 

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