( 4/9 + 7/9 -  2/9 ) x 19/24  = 1 x 19/24 = 19/24

\(=\dfrac{19}{24}\times\left(\dfrac{4}{9}+\dfrac{7}{9}-\dfrac{2}{9}\right)=\dfrac{19}{24}\times1=\dfrac{19}{24}\)

\(\dfrac{19}{24}\times\left(\dfrac{4}{9}+\dfrac{7}{9}-\dfrac{2}{9}\right)\)

\(=\dfrac{19}{24}\times1=\dfrac{19}{24}\)

200/2009

\(=\dfrac{19}{8}.\dfrac{16}{9}+\dfrac{19}{8}.\dfrac{2}{9}-\dfrac{19}{8}.1=\dfrac{19}{8}.\left(\dfrac{16}{9}+\dfrac{2}{9}-1\right)\)

\(=\dfrac{19}{8}.1=\dfrac{19}{8}\)

\(\dfrac{19}{8}\times\dfrac{16}{9}+\dfrac{19}{8}\times\dfrac{2}{9}-\dfrac{19}{8}\)

\(=\dfrac{19}{8}\times\left(\dfrac{16}{9}+\dfrac{2}{9}-1\right)\)

\(=\dfrac{19}{8}\times1\)

\(=\dfrac{19}{8}\)

Phương pháp giải:

- Tính giá trị của mỗi vế

- So sánh rồi điền dấu thích hợp vào chỗ trống. 

Lời giải chi tiết:

19 + 7 < 19 + 9            17 + 7 < 17 + 9

17 + 9 = 19 + 7            37 + 15 < 55 − 1

38 − 8 = 23 + 7            28 − 3 > 17 + 6

Dể quá

d: \(-37\cdot\left(-19\right)+37\left(-19\right)\)

\(=-19\left(-37+37\right)\)

\(=-19\cdot0=0\)

e: \(\left(29-9\right)\cdot\left(-9\right)+\left(-13-7\right)\cdot21\)

\(=20\cdot\left(-9\right)+\left(-20\right)\cdot21\)

\(=-20\left(9+21\right)\)

\(=-20\cdot30=-600\)

h: \(12\cdot\left(-47\right)+12\left(-19\right)+\left(-66\right)\cdot88\)

\(=12\left(-47-19\right)+\left(-66\right)\cdot88\)

\(=\left(-66\right)\cdot12+\left(-66\right)\cdot88\)

\(=-66\left(12+88\right)\)

\(=-66\cdot100=-6600\)

-1210/1767

a, theo thứ tự tăng dần : -16/19;-14/19;-12/19;-11/19;-9/19;-3/19;-1/19

b, theo thứ tự tăng dần :-10/11;-10/9;-10/8;-10/7;-10/4;-10/3;-10/2

a, theo thứ tự tăng dần : -16/19;-14/19;-12/19;-11/19;-9/19;-3/19;-1/19

b, theo thứ tự tăng dần :-10/11;-10/9;-10/8;-10/7;-10/4;-10/3;-10/2

15/19 . 17/19 + 15/19 . 10/9 - (-7/19)

= 15/19 . (17/19 + 10/19) + 7/19

= 15/19 . 27/19 + 7/19

= 405/361 + 7/19

= 538/361

B=(\(\left(\dfrac{4}{9}+\dfrac{5}{9}\right).\left(\dfrac{-1}{19}\right)\)

   =1.\(\dfrac{-1}{19}\)

   =\(\dfrac{-1}{19}\)

=(-1/19)x(4/9+5/9)

=(-1/19)x(9/9)

=(-1/19)x1

=-1/19