\(a/ (- 25).(- 125).(- 4). (- 8)=[(-25).(-4)].[(-125).(-8)] =100.1000=100000\)

a/(−25).(−125).(−4).(−8)

= [(−25).(−4)].[(−125).(−8)]

= 100.1000

=100000

b/ (-50) . (-80) . (-2) . (-9)

= [(-50) . (-20)] . [ (-80) . (-9) ]

=         100        .       720

=                 72000

\((\frac{9}{25}-2.18):\left(3\frac{4}{5}-0,2\right)\)

=-1,82 : 4

=-0,455

\(\left(\frac{9}{25}-2.18\right):\left(3\frac{4}{5}-0,2\right)\)

= -1,82:4=-0,455

\(25\cdot\left(-4\right)-54:9+\left(-48\right):\left(-8\right)=-100-6+6=-100\)

25.(-4)-54:9+(-48):(-8)

=-100-6+6

=-106+6

=-100

a)\(-\dfrac{2}{5}.\dfrac{4}{7}+\dfrac{-3}{5}.\dfrac{2}{7}+\dfrac{-3}{5}\) 

=\(-\dfrac{2}{5}.\dfrac{4}{7}+\dfrac{3}{7}.\dfrac{-2}{5}+\dfrac{-3}{5}\)

=\(-\dfrac{2}{5}.\left(\dfrac{4}{7}+\dfrac{3}{7}\right)+\dfrac{-3}{5}\) 

=\(\dfrac{-2}{5}.1+\dfrac{-3}{5}\) 

=\(-\dfrac{2}{5}+\dfrac{-3}{5}\) 

=\(-\dfrac{5}{5}\) = -1

\(\dfrac{5}{9}.\dfrac{14}{17}+\dfrac{1}{17}.\dfrac{5}{9}+\dfrac{2}{9}+\dfrac{5}{12}\)

=\(\dfrac{5}{9}.\left(\dfrac{14}{17}+\dfrac{1}{17}\right)+\dfrac{2}{9}+\dfrac{5}{12}\) 

=\(\dfrac{5}{9}.\dfrac{15}{17}+\dfrac{2}{9}+\dfrac{5}{12}\) 

=\(\dfrac{25}{51}+\dfrac{2}{9}+\dfrac{5}{12}\)

=\(\dfrac{691}{612}\)

\(-\dfrac{4}{25}:\dfrac{11}{79}+\dfrac{15}{11}:\dfrac{25}{79}\)

=\(-\dfrac{4}{25}.\dfrac{79}{11}+\dfrac{15}{11}.\dfrac{79}{25}\)

=\(-\dfrac{4}{25}.\dfrac{79}{11}+\dfrac{15}{25}.\dfrac{79}{11}\) 

=\(\left(-\dfrac{4}{25}+\dfrac{15}{25}\right).\dfrac{79}{11}\)

=\(\dfrac{11}{25}.\dfrac{79}{11}\) 

=\(\dfrac{79}{25}\)

\(=\left(-\dfrac{1}{6}-\dfrac{5}{6}\right)+\left(\dfrac{25}{9}+\dfrac{2}{9}\right)=-1+3=2\)

Câu 6: Tính bằng cách hợp lí:

 25/9 - 1/6 + 4/18 -5/6 = (25/9+4/18)+(-1/6-5/6)

                                   =3-1

                                  =2

\(=\dfrac{25}{9}-\dfrac{1}{6}-\dfrac{2}{9}-\dfrac{5}{6}\\ =\left(\dfrac{25}{9}-\dfrac{2}{9}\right)+\left(\dfrac{5}{6}-\dfrac{1}{6}\right)\\ =\dfrac{23}{9}+\dfrac{2}{3}\\ =\dfrac{23+6}{9}=\dfrac{29}{9}\)

a) \(=\frac{\left(\frac{9}{25}-36\right)}{\frac{19}{5}+\frac{1}{5}}=\frac{\frac{9}{25}-\frac{900}{25}}{\frac{20}{5}}=\frac{-891}{25}:4\)\(=\frac{-891}{25\cdot4}=\frac{-891}{100}=-8,91\)

b) \(=12\cdot\frac{\left(-2\right)^2}{3^2}+\frac{4}{3}=12\cdot\frac{4}{9}+\frac{4}{3}\)\(=\frac{48}{9}+\frac{4}{3}=\frac{48}{9}+\frac{12}{9}=\frac{60}{9}\)

(9/25-2.18) : (19/5+0,2) mà bạn

a. ( 4 x 25 ) x (5 x 9)

= 100 x 45

= 4500

b. (2008 x4) - ( 2008 x 4)

= 0

1) 125.(-24) + 24.225.

\(=24\left(-125+225\right)=24.100=2400.\)

2) 512.(2 – 128) – 128. (-512).

\(=512\left(2-128+128\right)=512.2=1024.\)