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![](https://rs.olm.vn/images/avt/0.png?1311)
TA CÓ :
\(A=a,53+4,b6+2,9c\)
\(\Rightarrow100A=100\times\left(a,53+4,b6+2,9c\right)\)
\(100A=\overline{a53}+\overline{4b6}+\overline{29c}\)
\(100A=100a+53+406+10b+290+c\)
\(100A=\left(100a+10b+c\right)+\left(53+406+290\right)=\overline{abc}+749\)
TA LẠI CÓ :
\(B=a,bd+8,3c-0,8d\)
\(\Rightarrow100B=100\times\left(a,bd+8,3c-0,8d\right)\)
\(100B=\overline{abd}+\overline{83c}-\overline{8d}\)
\(100B=100a+10b+d+830+c-80-d\)
\(100B=\left(100a+10b+c+d-d\right)+\left(830-80\right)=\overline{abc}+750\)
VÌ abc + 749 < abc + 750
=> 100A < 100B
=> A < B
VẬY , \(A< B\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a<b
Giải thích các bước giải:
a= a+ a,53+ 4,b6+0,b +2,9 +0,0c= a,bc+7,49
b= a,b+ 0,0d+8,c+0,0c-0,8-0,0d= a,bc=7,5
vì a,bc+7,49<a,bc +7,5 nên a< b
\(A=a,35+4,b6+2,9c\)
\(\Rightarrow100A=100\times\left(a,35+4,b6+2,9c\right)\)
\(100A=\overline{a53+4b6+29c}\)
\(100A=100a+53+406+10b+290+c\)
\(100A=\left(100a+10b+c\right)+\left(53+406+209\right)=\overline{abc+749}\)
Ta lại có :
\(B=a,bd+8,3c-0,8d\)
\(\Rightarrow100B=100\times\left(a,bd+8,3c-0,8d\right)\)
\(100B=\overline{abd+83c-8d}\)
\(100B=\overline{abd+\overline{83c-8d}}\)
\(100B=100a+10b+d+830+c-80-d\)
\(100B=\left(100a+10b+c+d-d\right)+\left(830-80\right)=\overline{abc+750}\)
Vì \(^{\overline{abc+749< abc+750}}\)
\(\Rightarrow100A< 100B\)
Vậy \(A< B\)
![](https://rs.olm.vn/images/avt/0.png?1311)
A=(a+0,b+0,0c)+(0,53+4,06+2,90)=a,bc+7,49 B=a,bd+8,3+0,0c-0,8-0,0d =(a,bd+0,0c-0,0d)+(8,3-0,8) =a,bc+7,5 Vậy B>A
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{54\times107-53}{53\times107+54}=\dfrac{53\times107+53-53}{53\times107+54}=\dfrac{53\times107}{53\times107+54}< 1\)
\(\dfrac{135\times269-133}{134\times269+135}=\dfrac{134\times269+269-133}{134\times269+135}=\dfrac{134\times269+136}{134\times269+135}>1\)
\(\Rightarrow\dfrac{54\times107-53}{53\times107+54}< \dfrac{135\times269-133}{134\times269+135}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 19993 x 19997
=19993 x 19995 +19993 x 2
19995 x 19995
=19993 x 19995 +19995 x 2
vì 19995 x 2 > 19993 x 2 nên 19993 x 19997 < 19995 x 19995
b)53 x 35 -18 = 53 x 34 -18 + 53
=53 x 34 +(53-18)
=53 x 34 + 35
=> 53 x 35 -18 = 53 x 34 + 35
chúc bạn học tốt nha
I don't now !
very easy
you can do
...................
![](https://rs.olm.vn/images/avt/0.png?1311)
A=213061
B=136051
vay A > B
ok thank you sit down please