\(=\left(-50+19+143\right)-\left(-79+25+48\right)\)

\(=-50+19+143+79-25-48\)

\(=118\)

\(\left(-25\right)\left(75-45\right)-75\left(45-25\right)\)

\(\left(-25\right).30-75.20\)

\(=-2250\)

\(\left(-37-17\right).\left(-9\right)+35\left(-9-11\right)\)

\(-54.\left(-9\right)+35.\left(-20\right)\)

\(-763\)

Đánh mỏi tay quá

(-50+19+143)-(-79+25+48)

= 112 - -6

= 118

(-25)(75-45)-75(45-25)

=(-25) 30 - 75 20

= -750 - 1500

= -2250

(-37-17)(-9)+35(-9-11)

= 54 (-9)+ 35-20

= 486 + -700

= -214

(187-23)-(20-180)

= 164 - -160

= 324

512(2-128)-128(-512)

=512 (-126)-128(-512)

= 64512 - (-65536)

= 1024

17(-25)+25 21

= -425 + 525

= 100.

a)  

\(\dfrac{1}{2}=0,5;\dfrac{3}{4}=0,75;\dfrac{7}{5}=1,4;\dfrac{9}{8}=1,125;\dfrac{26}{25}=1,04;\dfrac{120}{125}=0,96\)

b) 

\(\dfrac{15}{25}=0,6;\dfrac{75}{25}=3;\dfrac{90}{300}=0,3;\dfrac{27}{36}=0,75;\dfrac{51}{85}=0,6\)

a,1/2=5/10;3/4=75/100;7/5=140/100;26/25=108/100;120/125=960/1000

b,15/25=60/100;75/25=300/100;90/300=3/10;27/36=3/4=75/100;

51/85=3/5=60/100;39/65=3/5=60/100

a) 0,5; 0,75; 1,4; 1,125; 1,04; 0,96; 0,6

b) 0,6; 3,0; 0,3; 0,75; 0,6 

45 - ( 75-39) + (-25)

= 45 - 36 + ( -25)

= 9 + (-25)

= -16

45-(75-39)+(-25)

=45-75+39-25

= -55+39

= -16

=25(24+48)+75(16+56)

=72*25+72*75

=72*100

=7200

\(25.24+25.48+75.16+75.56\) 

\(=25.\left(24+48\right)+75.\left(16+56\right)\)

\(=25.72+75.72\)  

\(=\left(25+75\right).72\) 

\(=100.72\) 

\(=7200\)

Đáp án cần chọn là: D

= 35 . 34 + 35 . 38 + 65 . (-75 ) + 65 . ( -45 )

= 35 . ( 34 + 38 ) + 65 . ( -75 - 45 ) 

= 35 . 72 + 65 . ( -120 )

= 2520 - 7800 

= -5280 

35.34+(-35).(-38)+65.(-75)+(-65).45

= 35 . 34 + 35 . 38 + 65 . (-75 ) + 65 . ( -45 )

= 35 . ( 34 + 38 ) + 65 . ( -75 - 45 ) 

= 35 . 72 + 65 . ( -120 )

= 2520 - 7800 

= -5280 

xin like

= 25 x 25 + 25 x 75 = 25x (25 + 75) = 25 x 100 = 2500

25+25+....+25+25+75+75+...+75 

=25.25+75.25

=25(25+75)

=25.100

=2500

Lấy 1 số 25 ghép với 1 số 75 thì ta có:

(25+75)+(25+75)+...+(25+75)=100 x 25 = 2500

1/\(\left(-12\right)\cdot46-12\cdot54=\left(-12\right)\cdot46+\left(-12\right)\cdot54\)

\(=\left(-12\right)\cdot\left(46+54\right)=\left(-12\right)\cdot100=-1200\)

2/\(3784+23-3785-15=3785+22-3785-15\)

\(=22-15=7\)

3/\(\left(-8\right)\cdot25\cdot\left(-2\right)\cdot4\cdot\left(-5\right)\cdot125\)

\(=\left[\left(-8\right)\cdot125\right]\cdot\left[25\cdot4\right]\cdot\left[\left(-5\right)\cdot\left(-2\right)\right]\)

\(=\left(-1000\right)\cdot100\cdot10=-1000000\)

4/\(19\cdot25+9\cdot95+19\cdot30=19\cdot\left(25+30\right)+9\cdot95\)

\(=19\cdot55+9\cdot95=95\cdot11+9\cdot95=95\cdot\left(11+9\right)=20\cdot95=1900\)

5/\(\left(-50+19+143\right)-\left(-79+25+48\right)\)

\(=\left(-50\right)+19+143+79-25-48\)

\(=118\)

6/\(\left(-25\right)\cdot\left(75-45\right)-75\cdot\left(45-25\right)\)

\(=\left(-25\right)\cdot30+\left(-25\right)\cdot3\cdot20\)

\(=\left(-25\right)\cdot\left(30+60\right)=\left(-25\right)\cdot90=-2250\)

7/\(\left(-37-17\right)\cdot\left(-9\right)+35\left(-9-11\right)\)

\(=\left(-54\right)\cdot\left(-9\right)+35\cdot\left(-20\right)\)

\(=486+\left(-700\right)=-214\)

8/\(\left(187-23\right)-\left(20-180\right)\)

\(=187-23-20+180=324\)

9/\(512\cdot2-128\cdot\left(-512\right)\)

\(=512\cdot2+128\cdot512=512\cdot\left(2+128\right)\)

\(=512\cdot130=66560\)

10/\(17\cdot\left(-25\right)+25\cdot21\)

\(=17\cdot\left(-25\right)-\left(-25\right)\cdot21=\left(-25\right)\cdot\left(17-21\right)\)

\(=\left(-25\right)\cdot\left(-4\right)=100\)

Chúc bạn học tốt.