a, ( -18 + 25 ) - ( 125 - 18 + 25 )

= -18+25-125+18-25

= (-18+18) +(25-25) -125

= 0+0-125

= -125

b, 45 . ( 18 - 15 ) -18 . ( 45 + 45 )

= 45.18 - 45.15 -18.45 +18.45

= 45(18-15-18+18)

= 45.3=135

a ) = -18 + 25 - 125 + 18 - 25

= (-18 + 18 ) - ( 25 -25 ) + 125

= 0              -    0            + 125

=125

a) 25.(-45)+(-25).55

=25.(-45)+25.(-55)

=25.(-45-55)

=25.(-100)

=-2500

b)(-75).18+18.(-25)+(-72).100

=18.(-75-25)+(-72).100

=18.(-100)+72.(-100)

=(-100).(18+72)

=(-100).100

=-10000

sẽ bằng 1800

18x(25+75)=1800

18*25+18*75

=18*(25+75)

=18*100

=1800

\(a)-7/25*(11/13+2/13)-18/25=-7/25*1-18/25=-7/25-18/25=-25/25=-1\)

\(=-\dfrac{7}{25}\left(\dfrac{11}{13}+\dfrac{2}{13}\right)-\dfrac{18}{25}=-\dfrac{7}{25}.1-\dfrac{18}{25}=-\dfrac{25}{25}=-1\)

\(\dfrac{-7}{25}.\dfrac{11}{13}+\dfrac{-7}{25}.\dfrac{2}{13}-\dfrac{18}{25}\\ =\dfrac{-7}{25}\left(\dfrac{11}{13}+\dfrac{2}{13}\right)-\dfrac{18}{25}\\ =\dfrac{-7}{25}.\dfrac{13}{13}-\dfrac{18}{25}\\ =\dfrac{-7}{25}.1-\dfrac{18}{25}\\ =\dfrac{-7}{25}-\dfrac{18}{25}\\ =\dfrac{-25}{25}\\ =-1\)

22.23=(20+2).23=460+46=506

44.101=44(100+1)=4400+44=4444

25.105=25(100+5)=250+125=375

a. `306xx 18-306 xx 8=306 xx (18-8) =306 xx 10=3060`

b. `9 xx 9+25xx9 +33 xx18`

`=9 xx9 + 25 xx 9 + 33 xx 2 xx 9`

`=9x (9+25+33xx2)`

`=9 xx (9+25+66)`

`=9 xx 100`

`=900`

a) \(306\cdot18-306\cdot8=306\cdot10=3060\)

b) \(9\cdot9+25\cdot9\cdot33\cdot18=9\cdot9\cdot\left(1+25\cdot33\cdot2\right)=81\cdot1651=133731\)

a. 

b. 

Hướng dẫn giải:

\(=\dfrac{23}{100}-\dfrac{18}{100}+\dfrac{25}{100}\cdot\dfrac{1}{5}=\dfrac{23}{100}-\dfrac{18}{100}+\dfrac{5}{100}=\dfrac{10}{100}=\dfrac{1}{10}\left(=10\%\right)\)

1/10

1)
a) \(34,2:36=0,95\)
b) \(36,18:18=2,01\)
c) \(5,05:25=0,202\)
d) \(17,25:75=0,23\)
2) 
a) \(75,52:32=2,36\)
b) \(4,68:13=0,36\)
c) \(81,6:34=2,4\)
d) \(134,4:42=3,2\)
3) 
a) \(882:36=24,5\)
b) \(78:24=3,25\)
c) \(3:15=0,2\)
d) \(15:75=0,2\)
4) 
a) \(3:75=0,04\)
b) \(750:300=2,5\)
c) \(390:12=32,5\)
d) \(54:24=2,25\)