Question

[nhee phạm]

 bài 1 tính : ( 1- 1/99 ) x ( 1- 1/100) x....x ( 1- 1/2006 ) 

bài 2 : không quy đồng mẫu số hãy so sánh hai phân sóo : 111/333 và 2222/4444 

cố gắng giúp mình vs ạ 

Answer 1

[Kiều Vũ Linh]

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

Answer 2

[Toru]

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