a) ta có \(\frac{1234}{1235}=1-\frac{1}{1235}\)

\(\frac{4319}{4320}=1-\frac{1}{4320}\)

vì \(\frac{1}{1235}>\frac{1}{4320}\Rightarrow1-\frac{1}{1235}< 1-\frac{1}{4320}\)

\(\Rightarrow\frac{1234}{1235}< \frac{4319}{4320}\)

b) ta có \(\frac{1234}{1244}=1-\frac{10}{1244}\)

\(\frac{4321}{4331}=1-\frac{10}{4331}\)

vì \(\frac{10}{1244}>\frac{10}{4331}\Rightarrow1-\frac{10}{1244}< 1-\frac{10}{4331}\)

\(\Rightarrow\frac{1234}{1244}< \frac{4321}{4331}\)

\(\Rightarrow\frac{-1234}{1244}>\frac{-4321}{4331}\) 

A)

1- 1234/1235= 1/1235

1- 4319/4320= 1/4320

Vậy 1/1235 > 1/4320

1234/1235 > 4329/4320

Đ/s:...

Ko chắc, sai bỏ qa

a) 

\(\frac{1234}{1235}=1-\frac{1}{1235}\)

\(\frac{4319}{4320}=1-\frac{1}{4320}\)

Ta có: 4320>1235 => \(\frac{1}{4320}< \frac{1}{1235}\Rightarrow1-\frac{1}{4320}>1-\frac{1}{1235}\Rightarrow\frac{4319}{4320}>\frac{1234}{1235}\)

b) Em tham khảo link Câu hỏi của Jenna - Toán lớp 7 - Học toán với OnlineMath

Ta có:

\(\dfrac{-1234}{1244}=-1+\dfrac{10}{1244}\)

\(\dfrac{-4321}{4331}=-1+\dfrac{10}{4331}\)

Vì \(\dfrac{10}{1244}>\dfrac{10}{4331}\)

\(\Rightarrow-1+\dfrac{10}{1244}>-1+\dfrac{10}{4331}\)

hay \(\dfrac{-1234}{1244}>\dfrac{-4321}{4331}\)

\(\dfrac{1234}{1244}< \dfrac{1234+3037}{1244+3037}=\dfrac{4331}{4321}\)

\(\Rightarrow\dfrac{1234}{1244}< \dfrac{4331}{4321}\)

\(\Rightarrow-\dfrac{1234}{1244}>-\dfrac{4331}{4321}\)

\(\Rightarrow\dfrac{-1234}{1244}>\dfrac{4331}{-4321}\)

Thành ko chép mạng nhé

a) \(\frac{1}{1235}>\frac{1}{4320}\Rightarrow-\frac{1}{1235}< -\frac{1}{4320}\Rightarrow1-\frac{1}{1235}< 1-\frac{1}{4320}\Rightarrow\frac{1234}{1235}< \frac{4319}{4320}.\)

b) \(\frac{10}{1244}< \frac{10}{4331}\Rightarrow\frac{10}{1244}-1< \frac{10}{4331}-1\Rightarrow-\frac{1234}{1244}< -\frac{4321}{4331}\)

a)  Ta có:

1234/1235 = 1 - 1/1235

4319/4320 = 1 - 1/4320

Vì 1/1235 > 1/4320

=> 1234/1235 < 4319/4320

b) -1234/1244 = -1 + 10/1244

-4321/4331 = -1 + 10/4331

Vì 10/1244 > 10/4331

=> -1 + 10/4331 > -1/4331

Ủng hộ mk nha ♡_♡

mình mới học lớp 4 nên ko bít

em ko biết,xin lỗi chị nhiều lắm

1234 phần 1235 bằng 4319 phần 4320

\(\frac{-1234}{1244}\)và  \(\frac{-4321}{4331}\)

Ta có: 

\(\frac{-1234}{1244}=\frac{-1234\times4331}{1244\times4331}=\frac{-5344454}{5387764}\)

  \(\frac{-4321}{4331}=\frac{-4321\times1244}{1244\times4331}=\frac{-5375324}{5387764}\)

Ta thấy: \(\frac{-5344454}{5387764}>\frac{-5375324}{5387764}\)

\(\Rightarrow\frac{-1234}{1244}>\frac{-4321}{4331}\)

So sánh

−1234/1244    >       −4321/4331 

bằng nhau

\(\dfrac{333}{337}=\dfrac{337}{337}-\dfrac{4}{337}=1-\dfrac{4}{337}\\ \dfrac{277}{281}=\dfrac{281}{281}-\dfrac{4}{281}=1-\dfrac{4}{281}\\ \)

Ta thấy : \(\dfrac{4}{337}< \dfrac{4}{281}\)

\(=>1-\dfrac{4}{337}>1-\dfrac{4}{281}\\ =>\dfrac{333}{337}>\dfrac{277}{281}\)

a) ta có:  \(1-\frac{2012}{2013}=\frac{1}{2013}\)

                 \(1-\frac{2013}{2014}=\frac{1}{2014}\)

mà \(\frac{1}{2013}>\frac{1}{2014}\) nên   \(\frac{2013}{2014}>\frac{2012}{2013}\)

sao giống lớp 4 thế ta

13 x 64 = 832

38 x 21 = 798

Do đó: 13 x 64 > 38 x 21

=> 13 x 64 x 1/64 x 1/38 > 38 x 21 x 1/64 x 1/38

=> 13/38 > 21/64

Ta có : 

\(\frac{13}{38}>\frac{13}{39}\left(38< 39\right)\)

\(\Rightarrow\frac{13}{38}>\frac{1}{3}\left(1\right)\)

\(\frac{21}{64}< \frac{21}{63}\left(64>63\right)\)

\(\Rightarrow\frac{21}{64}< \frac{1}{3}\left(2\right)\)

Từ \(\left(1\right);\left(2\right)\)

\(\Rightarrow\frac{21}{64}< \frac{1}{3}< \frac{13}{38}\)

\(\Rightarrow\frac{21}{64}< \frac{13}{38}\)

Vậy \(\frac{21}{64}< \frac{13}{38}\)

~ Ủng hộ nhé 

P/s :

Sử dụng phân số trung gian vào bài toán này : 

~ Ủng hộ nhé