so sánh a=2525/2626 và b=20202020/20212021
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\(\dfrac{121212}{242424}+\dfrac{1313}{2626}+\dfrac{20212021}{40424042}\)
= \(\dfrac{12}{24}+\dfrac{13}{26}+\dfrac{2021}{4042}\)
= \(\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{2}\)
= \(\dfrac{3}{2}\)
121212/242424+1313/2626+20212021/404244024
= 1/2+1/2+1/2
=3/2

A = 19,19 x 2525,25
A = 19 x 1,01 x 25 x 101,01
B = 25,25 x 1919,19
B = 25 x 1,01 x 19 x 101,01
Vậy A = B
\(\text{+)}\)
\(A=19,19.2525,25\)
\(A=19.1,01.25.101,01\)
\(\text{+)}\)
\(B=25,25.1919,19\)
\(B=25.1,01.19.101,01\)
\(\Rightarrow A=B\)

\(\frac{25}{26}=\frac{2525}{2626}=\frac{252525}{262626}=\frac{25252525}{26262626}\)
Ta có:
2525/2626 = 25 × 101/26 × 101 = 25/26
252525/262626 = 25 × 10101/26 × 10101 = 25/26
25252525/26262626 = 25 × 1010101/26 × 1010101 = 25/26
Chứng tỏ các phân số trên đều = nhau

\(A=\dfrac{1919}{100}\times\dfrac{252525}{100}=\dfrac{19\times101}{100}\times\dfrac{25\times10101}{100}=\dfrac{19\times25\times101\times10101}{100\times100}\)
\(B=\dfrac{2525}{100}\times\dfrac{191919}{100}=\dfrac{25\times101}{100}\times\dfrac{19\times10101}{100}=\dfrac{19\times25\times101\times10101}{100\times100}\)
Vậy \(A=B\)
A = 19,19 x 2525,25 = 19 x 1,01 x 25 x 101,01
B = 25,25 x 1919,19 = 25 x 1,01 x 19 x 101,01
Vậy A = B


ta có: \(\frac{1717}{2525}=\frac{17}{25}\)
\(\frac{515151}{727272}=\frac{51}{72}=\frac{17}{24}>\frac{17}{25}\)
\(\Rightarrow\frac{1717}{2525}< \frac{515151}{727272}\)

\(\frac{1717}{2525}=\frac{17}{25};\frac{515151}{727272}=\frac{51}{72}\)
Ta có : \(\frac{17}{25}<\frac{51}{72}\)nên \(\frac{1717}{2525}<\frac{515151}{727272}\)
\(\frac{1717}{2525}=\frac{17}{25}\)
\(\frac{515151}{727272}=\frac{17}{24}\)
Cùng tử, ta có : 25 > 24
=> \(\frac{17}{25}<\frac{17}{24}\)
hoặc \(\frac{1717}{2525}<\frac{515151}{727272}\)

A)1212/1313<1313/1414.B)1717/2525<515151/727272.23/28,7/9,5/7,11/18

1111 + 1212 + 1313 + 1414
= 11 x 101 + 12 x 101 + 13 x 101 + 14 x 101
=( 11 + 12 +13 +14 ) x 101
=50 x 101
= 5050
2222 + 2323 +2424 +2525
= 22 x 101 + 23 x 101 + 24 x 101 + 25 x 101
= ( 22 +23 + 24 + 25 ) x 101
=94 x 101
= 9494
A = \(\frac{2525}{2626}\) \(=\frac{2525:101}{2626:101}\) = \(\frac{25}{26}\) = 1 - \(\frac{1}{26}\)
B = \(\frac{2020:1001}{20212021:1001}\) = \(\frac{2020}{2021}\) = 1 - \(\frac{1}{2021}\)
Vì \(\frac{1}{26}\) > \(\frac{1}{2021}\)
Nên A < B(hai phân số, phân số có phần bù lớn hơn thì phân số đó nhỏ hơn.
Có :
`2525 = 5^2 xx 101`
`2626 = 2 xx 3 xx 101`
`=> ƯCLN(2525;2626) = 101`
`=> a = 2525/2626 = (2525:101)/(2626:101) = 25/26`
Lại có : `20202020 = 2^2 xx 5 xx 73 xx 101 xx 137`
` 20212021 = 43 xx 47 xx 73 xx 137`
`=> ƯCLN (20202020 ; 20212021) = 73 xx 137 = 10001`
`=> b = 20202020/20212021 = (20202020 : 10001)/(20212021 :10001) = 2020/2021`
Có : `a=25/26 = (25*2021)/(26*2021) = 50525/52546`
`b=2020/2021 = (2020 * 26)/(2021*26) = 52520/52546`
Vì `50525<52520`
`=> 50520/52546 < 52520/52546`
`=> a<b`
Vậy `a<b`