Bài 10:

A. Ta có:

\(\dfrac{99}{100}< 1\) ; \(\dfrac{9}{8}>1\)

Nên \(\dfrac{99}{100}< \dfrac{9}{8}\)

B. \(\dfrac{7}{12}< \dfrac{7}{8}\)

Bài 1

\(\left(1-\dfrac{1}{99}\right)\times\left(1-\dfrac{1}{100}\right)\times...\times\left(1-\dfrac{1}{2006}\right)\)

\(=\dfrac{98}{99}\times\dfrac{99}{100}\times...\times\dfrac{2005}{2006}\)

\(=\dfrac{98}{2006}\)

\(=\dfrac{49}{1003}\)

Bài 2

\(\dfrac{111}{333}=\dfrac{111:111}{333:111}=\dfrac{1}{3}\)

\(\dfrac{2222}{4444}=\dfrac{2222:2222}{4444:2222}=\dfrac{1}{2}\)

Do \(3>2\Rightarrow\dfrac{1}{3}< \dfrac{1}{2}\)

Vậy \(\dfrac{111}{333}< \dfrac{2222}{4444}\)

Bài 1.

\(\left(1-\dfrac{1}{99}\right)\times\left(1-\dfrac{1}{100}\right)\times...\times\left(1-\dfrac{1}{2006}\right)\)

\(=\dfrac{98}{99}\times\dfrac{99}{100}\times...\times\dfrac{2005}{2006}\)

\(=\dfrac{98\times99\times...\times2005}{99\times100\times...2006}\)

\(=\dfrac{98}{2006}\)

\(=\dfrac{49}{1003}\)

Bài 2.

Có: \(\dfrac{111}{333}=\dfrac{111}{3\times111}=\dfrac{1}{3}\)

\(\dfrac{2222}{4444}=\dfrac{2222}{2\times2222}=\dfrac{1}{2}\)

Vì \(\dfrac{1}{3}< \dfrac{1}{2}\) nên \(\dfrac{111}{333}< \dfrac{2222}{4444}\)

a: 5/7<6/7

b: 17/13>1>45/52

c: 4/3>1>99/100

Tham khảo

a, 5<6 => 5/7 < 6/7

b, 17/13 > 1   45/52< 1  => 45/52 < 17/13

c, 8/7 > 1    7/8< 1   =>  7/8 >< 8/7

d, 9/5 > 1   5/8 < 1    => 9/5 > 5/8

+)

\(\frac{2}{3}=0,\left(6\right)\)

\(\frac{3}{4}=0,75\)

vi \(0,\left(6\right)< 0,75\) nen \(\frac{2}{3}< \frac{3}{4}\)

+)  \(\frac{5}{6}=0,8\left(3\right)\)

   \(\frac{6}{7}=0,85714\)

vi \(0,8\left(3\right)< 0,85714\) nen \(\frac{5}{6}< \frac{6}{7}\)

a ) \(\frac{2}{3}\)và \(\frac{3}{4}\)

Ta có : \(1-\frac{2}{3}=\frac{1}{3}\)và \(1-\frac{3}{4}=\frac{1}{4}\)

Vì : \(\frac{1}{3}>\frac{1}{4}\)

Nên : \(\frac{2}{3}< \frac{3}{4}\)

b ) \(\frac{5}{6}\)và \(\frac{6}{7}\)

Ta có : \(1-\frac{5}{6}=\frac{1}{6}\)và \(1-\frac{6}{7}=\frac{1}{7}\)

Vì : \(\frac{1}{6}>\frac{1}{7}\)

Nên : \(\frac{5}{6}< \frac{6}{7}\)

ta có 2/6=8/24

         5/8=15/24

  vậy ta có 15/24>8/24 nên 5/8>2/6

\(\frac{2}{6}=\frac{2.8}{6.8}=\frac{16}{48}\)

\(\frac{5}{8}=\frac{5.6}{8.6}=\frac{30}{48}\)

Vì \(\frac{16}{48}< \frac{30}{48}\) nên \(\frac{2}{6}< \frac{5}{8}\)

Tk cho mk nha 

quy đồng được:8/24 và 15/24.vì 8/24 nhỏ hơn 15/24 nên 2/6 nhỏ hơn 5/8.đúng đó.tk nha

97/100=1-3/100

119/122=1-3/122

mà 3/100>3/122

nên 97/100<119/122

97/100 > 119/122

97/100 lớn 119/122

Ta có: 1 - 97/100 = 3/100

1 - 119/122 = 3/122

Có: 3/100 > 3/122

\(\Rightarrow\) 97/100 < 119/122

Ta có :

`1-12/13 = 1/13`

`1-13/14=1/14`

`-> 1 xx 14 > 1xx 13`

`-> 1/13 > 1/14`

Vậy `12/13 > 13/14`

Ta có :

\(1-\dfrac{12}{13}=\dfrac{1}{13}\)

\(1-\dfrac{13}{14}=\dfrac{1}{14}\)

mà \(\dfrac{1}{13}>\dfrac{1}{14}\)

\(\Rightarrow\dfrac{12}{13}< \dfrac{13}{14}\)

\(\dfrac{12}{13}\) = 1 - \(\dfrac{1}{13}\)

\(\dfrac{13}{14}\) = 1 - \(\dfrac{1}{14}\)

Vì \(\dfrac{1}{13}\) > \(\dfrac{1}{14}\)

Nên \(\dfrac{12}{13}\)  < \(\dfrac{13}{14}\) (hai phân số phân số nào có phần bù lớn hơn thì phân số đó nhỏ hơn)

3/4 va 4/5

Quy dong len mau 20

15/20 va 16/20

15<16

Suy ra 15/20<16/20

3/4<4/5

b)5/8 va 4/9

Quy ddong len 72

40/72 va 32/72

40>32

40/72>32/72

Suy ra :5/8>4/9