`#3107.101107`

`a)`

Ta có:

\(\dfrac{2727}{3131}=\dfrac{2727\div27}{3131\div31}=\dfrac{27}{31}\)

Vì \(\dfrac{27}{31}=\dfrac{27}{31}\)

\(\Rightarrow\dfrac{27}{31}=\dfrac{2727}{3131}\)

`b)`

Ta có:

\(\dfrac{11}{31}=1-\dfrac{20}{31}=1-\dfrac{200}{310}\)

\(\dfrac{111}{311}=1-\dfrac{200}{311}\)

Vì \(\dfrac{200}{310}>\dfrac{200}{311}\)

\(\Rightarrow1-\dfrac{200}{310}< 1-\dfrac{200}{311}\)

\(\Rightarrow\dfrac{11}{31}< \dfrac{111}{311}.\)

27/31 = 2727/3131

11/31 bé hơn 111/311

\(a,\dfrac{2727}{3131}=\dfrac{2727:101}{3131:101}=\dfrac{27}{31}\\ Vậy:\dfrac{27}{31}=\dfrac{2727}{3131}\)

27/31<2727/3131

11/31<111/311

\(\frac{27}{31}=\frac{2727}{3131}=\frac{272727}{313131}\)

\(\frac{27}{31}=\frac{27.101}{31.101}=\frac{27.10101}{31.10101}\)

\(\frac{27}{31}=\frac{27}{31}=\frac{27}{31}\)

\(\Rightarrow\frac{27}{31}=\frac{2727}{3131}=\frac{272727}{313131}\)

\(\frac{27}{31}=\frac{2727}{3131}=\frac{272727}{313131}\)

\(\frac{27}{31}=\frac{27\cdot101}{31\cdot101}=\frac{27\cdot10101}{31\cdot10101}\)

\(\Rightarrow\frac{27}{31}=\frac{2727}{3131}=\frac{272727}{313131}\)

ai nhanh đúng thì đc 2 hoặc 3 k nhoa

a) Ta có :

\(-\dfrac{8}{31}=\dfrac{-8\cdot101}{31\cdot101}=\dfrac{-808}{3131}< \dfrac{-789}{3131}\)

BCNN(31,3131)=3131

-8/31=-8.101/31.101                           -789/3131=-789/3131

-8/31=-808/3131 

Vì -789/3131>-808/3131 nên -789/3131>-8/31

\(\dfrac{-8}{31}>\dfrac{-789}{3131}\)

12/27 và 1212/2727 

1212/2727 = 12/27 

vì 12/27 = 12/27 => 1212/2727 = 12/27

13/15 và 23 /25

13/15 x10/10 = 130 /150

23 /25 x 6/6 = 138 /150 

vì 130/150 < 138/150 

=> 13/15 < 23/25

Công thức 1:

Bước 1: Quy đồng hai phân số về cùng mẫu số.

Bước 2: So sánh hai phân số có cùng mẫu số đã quy đồng.

\(=>\frac{1212}{2727}\)\(=\frac{4}{9}\)

\(\frac{12}{27}\)\(=\frac{4}{9}\)

\(=>\frac{4}{9}=\frac{4}{9}\)\(=>\frac{12}{27}\)\(=\frac{1212}{2727}\)