Question

`A,2019*85+2019*25-2019*10`

`B 13/5*4/9+5/9*13/9`

Answer 1

`a)2019xx85+2019xx25-2019xx10`

`=2019xx(85+25-10)`

`=2019xx100=20190`

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`b)13/5xx4/9+5/9xx13/9`

`=13/9xx4/5+5/9xx13/9`

`=13/9xx(4/5+5/9)`

`=13/9xx61/45=793/405`

Hoặc:

`b)13/5xx4/9+5/9xx13/5`

`=13/5xx(4/9+5/9)`

`=13/5xx9/9=13/5`

Answer 2

A

2019.(85+25-10)=201 900

B

13/5 . (4/9+5/9)=13/5

học tốt ^^

Answer 3

\(\text{A) 2019 . 85 + 2019 . 25 - 2019 . 10}\)

\(\text{= 2019 . ( 85 + 25- 10)}\)

\(\text{= 2019 x 100}\)

\(\text{= 201900}\)

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B) \(\dfrac{13}{5}.\dfrac{4}{9}+\dfrac{5}{9}.\dfrac{13}{5}\)

\(=\dfrac{13}{5}.\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)

\(=\dfrac{13}{5}.\dfrac{9}{9}\)

\(=\dfrac{13}{5}.1=\dfrac{13}{5}\)

 

 

\(\dfrac{13}{9}.\dfrac{4}{9}+\dfrac{5}{9}.\dfrac{13}{9}\)

\(=\dfrac{13}{9}.\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)

\(=\dfrac{13}{9}.\dfrac{9}{9}\)

\(=\dfrac{13}{9}.1=\dfrac{13}{9}\)