a) 2.(-25).(-4).50              b) -125.5.(-8).2                 c) 16.50.(-25).(-250)

= (2.50).[(-25).(-4)]          = [(-125).(-8)].(2.5)             = 4.4.50.(-25).(-250)

=  100  .     100              =      1000    . 10               = [4.(-25)].[4.(-250)].50

=      10000                    =          10000                  = [(-100).(-1000)].50

                                                                           =       100000     .50

                                                                           =           5000000    

a) 2.(-25).(-4).50=(2.50).[(-25).(-4)]=100.100=10000

b)-125.5.(-8).2=[(-125).(-8)].(2.5)=1000.10=10000

c)16.50.(-25).(-250)=4.4.50.(-25).(-250)=[4.(-25)].[4.(-250)].50=(-100).(-1000).50=100000.50=5000000

\(\dfrac{8}{5}\cdot\dfrac{45}{17}\cdot\dfrac{-25}{16}\cdot\dfrac{-34}{9}=\dfrac{8\cdot5\cdot9\cdot25\cdot17\cdot2}{5\cdot17\cdot8\cdot2\cdot9}=\dfrac{25}{9}\) (bỏ đi các dấu trừ vì số âm nhân số âm là số dương)

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

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

=-100-6+6

=-106+6

=-100

a)    \(\left(-25\right).5.\left(-4\right).2\)

\(=\left[\left(-25\right).\left(-4\right)\right].\left(2.5\right)\)

\(=100.10=1000\)

b)   \(\left(-456\right)-\left(67-456\right)\)

\(=-456-67+456\)

\(=\left(456-456\right)-67\)

\(=67\)

a) ((-25).(-4)).5.2

=100.10

=1000

b) (-456)-67+456

=(-456)+(-67)+456

=0+-(-67)

=-67

c)78.45+-145.78

=78.(45+145)

=78.190

=Tự làm

a) (-25).5.(-4).2

= 5 . ( -4 ) . ( -25 ) . 2

= -20 . ( - 50 )

= 100

b) (-456) - (67 - 456)

= -456 - 67 + 456

= -456 + 456 - 67

= -67

c) 78.45+145.(-78)

= 78 . 45 + ( - 145 ) . 78

= 78 . ( -145 + 45 )

= 78 . 100

= 7800

d) 38.( 62-75) + 62.(-75 - 38)

= 38 . 62 - 38 . 75 + 62 . ( - 75 ) - 62 . 38

= 38 . 62 - 62 . 38 + 38 . 75 + 62 . ( - 75 )

= 0 + 38 . 75 + ( - 62 ) . 75

= 75 . ( - 62 + 38 )

= 75 . ( - 24 )

= - 1800

a) 125.(-4).(-8).7

= 125 . ( - 8 ) . ( - 4 ) . 7

= 1000 . ( - 28 )

= - 28000

c) 72.( 28 - 49) + 28. ( -49 - 72)

= 72 . 28 - 72 . 49 + 28 . ( - 49 ) - 28 . 72

= 72 . 28 - 28 . 72 + 72 . 49 + 28 . ( - 49 )

= 0 + 72 . 49 + ( - 28 ) . 49

= 49 . ( -28 + 72 )

= 49 . 44

= 2156

a) 5 . 125 . 2 . 41 . 8

= (5 . 8) . (125 . 2) . 41

= 40 . 250 . 41

= 10 000 . 41

= 410 000

b) 25 . 7 . 10 . 4

= (25 . 4 ) . (10 . 7)

= 100 . 70

= 7000

Chúc bạn học tốt!! ^^

a,5.125.2.41.8=(125.8).(2.5).41=1000.10.41=410000

b,25.7.10.4=(25.4).70=100.70=7000

c,8.12.125.2=(8.125).12.2=100.24=2400

d,4.36.25.50=(4.25).(2.50).18=100.100.18=180000

c) 8 . 12 . 125

= (125 . 8) . 12

= 1000 . 12

= 12 000

d) 4 . 36 . 25 . 50

= (25 . 4) . (50 . 36)

= 100 . 1800

= 180 000

Chúc bạn học tốt!! ^^

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

a/(−25).(−125).(−4).(−8)

= [(−25).(−4)].[(−125).(−8)]

= 100.1000

=100000

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

= [(-50) . (-20)] . [ (-80) . (-9) ]

=         100        .       720

=                 72000

may tinh cau a neu mun casch giai mk giai cho

\(0,25+25\%\times55+\dfrac{1}{4}\times45-\dfrac{2}{8}\)

\(=\dfrac{1}{4}+\dfrac{1}{4}\times55+\dfrac{1}{4}\times45-\dfrac{1}{4}\)

\(=\dfrac{1}{4}\times\left(1+55+45-1\right)\)

\(=\dfrac{1}{4}\times100\)

\(=25\)

\(0,25+25\%\times55+\dfrac{1}{4}\times45-\dfrac{2}{8}\)

\(=\dfrac{1}{4}+\dfrac{1}{4}\times55+\dfrac{1}{4}\times45-\dfrac{1}{4}\)

\(=\dfrac{1}{4}\times1+\dfrac{1}{4}\times55+\dfrac{1}{4}\times45-\dfrac{1}{4}\times1\)

\(=\dfrac{1}{4}+\left(1+55+45-1\right)\)

\(=\dfrac{1}{4}\times100\)

\(=0,25\times100\)

\(=25\)

\(#:)\)

Ta gộp để thành số tròn:(125.8).(4.25).9=1000.100.9=900 000