\(a,\frac{12345}{12342}=1+\frac{3}{12342}\)

    \(\frac{23457}{23455}=1+\frac{2}{23455}\)

Vì \(\frac{3}{12342}>\frac{2}{23455}\Rightarrow\frac{12345}{12342}>\frac{23457}{23455}\)

\(b,\frac{149}{150}=1-\frac{1}{150}\)

        \(\frac{4}{11}=1-\frac{7}{11}\)

Vì \(\frac{1}{150}< \frac{7}{11}\Rightarrow\frac{149}{150}>\frac{4}{11}\)

12345/12342 = 1 + 3/12342 = 1 + 1/ 4114 = 1 + 2/8228

23457/23455 = 1 + 2/23455

Có 1 + 2/8228 > 1 + 2/23455 => 12345/12342 > 23457/23455.

149/450 < 150/450 = 1/3

4/11 > 4/12 = 1/3

Vậy 149/450 < 4/11

kb voi mk nha

\(\frac{22}{7}\)> \(\frac{11}{5}\)vì 22 : 7 = 3,14 ; 11: 5 = 2,2

\(\frac{15}{59}\)< \(\frac{24}{97}\)vì 15 : 59 = 0,21 ; 24 : 97 = 0,24

\(\frac{11}{19}\)< \(\frac{13}{18}\)vì 11 : 19 = 0,57 ; 13 : 18 = 0,72

\(\frac{7}{10}\)> \(\frac{4}{9}\)vì 7 : 10 = 0,7 ; 4 : 9 = 0,44
 

Ủa 15:59 ko ra0,21

345\691>413\825

Giải 

Ta có: \(\frac{345}{691}\)<    \(\frac{345}{690}\)

            \(\frac{345}{690}\)= \(\frac{1}{2}\)=     \(\frac{413}{826}\)       \(\frac{1}{2}\)

              \(\frac{413}{826}\)< \(\frac{413}{825}\)

 Vậy      \(\frac{345}{691}\)<\(\frac{413}{825}\)

4/9>3/10

a)     \(\frac{2}{5}< \frac{8}{11}\)

b)     \(\frac{5}{7}>\frac{7}{15}\)

a​) 2/5 và 8/11                                                                            b) 5/7 và 7/15

2/5=0,4                                                                                      5/7=0,7142...

8/11=0,7272....                                                                          7/15=0,4666...

Vậy phân số 2/5<8/11                                                               Vậy phân số 5/7>7/15 

Vì

\(\frac{13}{27}\)= 0,481

\(\frac{16}{33}\)= 0,484

Nên :

\(\frac{13}{27}\)< \(\frac{16}{33}\)

a = 51 x 48 = 51 x ( 45 + 3 ) = 51 x 45 + 51 x 3

b = 54 x45 = (51 + 3 ) x 45 = 51 x45 + 3 x 45

ta thấy: 3 x 51 > 3 x 45 nên a > b

Ta có: A=51x48=51x(45+3) = 51x45+3x51

B= 54x45=(51+3)x45=51x45+3x45

Ta thấy 51x3>45x3 => 51x45+3x51>51x45+3x45 hay A>B