2/25=4/50=0,08

111/125=222/250=0,888

23/8=46/16=2,875             76/4=152/8=19      42/25=84/50=1,68    370/50=740/100=7,4

2/25=8/100=0,08

111/125=888/1000=0,888

23/8=2875/1000=2,875

76/4=1900/100=19

42/25=168/100=1,68

370/50=740/100=7,4

2/25=8/100=0,8

111/125=888/1000=0,888

23/8=2875/1000=2,875

76/4=1900/100=1,9

42/25=168/100=1,68

370/50=740/100=7,4

2/25=4/50=0,08

111/125=222/250=0,888

23/8=46/16=2,875             76/4=152/8=19      42/25=84/50=1,68    370/50=740/100=7,4

\(\frac{9}{5}=\frac{18}{10}=1,8\)

\(\frac{2}{25}=\frac{8}{100}=0,08\)

\(\frac{111}{125}=\frac{888}{1000}=0.888\)

\(\frac{23}{8}=\frac{2875}{1000}=2,875\)

\(\frac{76}{4}=\frac{1900}{100}=19\)

\(\frac{9}{5}=\frac{18}{10}=1,8\)

\(\frac{2}{25}=\frac{8}{100}=0,08\)

\(\frac{111}{125}=\frac{111.8}{125.8}=\frac{888}{1000}=0,888\)

\(\frac{76}{4}=19\)

\(\frac{23}{8}=\frac{23.125}{8.125}=\frac{2875}{1000}=2,875\)

\(\frac{42}{25}=\frac{42.4}{25.4}=\frac{168}{100}=1,68\)

\(\frac{370}{50}=\frac{37}{5}=\frac{37.2}{5.2}=\frac{74}{10}=7,4\)

18/10=1,8

8/100=0.08

9/5 =18/10=1,8
 2/25 =8/100=0,08
23/8 =2874/1000=2,874
76/4 =1900/100=19
42/25 =168/100=1,68

9/5 = 18/10 = 1,8

2/25 = 8/100 = 0,08

23/8 = 2875/1000 = 2,875

76/4 = 1900/100 = 19,00 = 19

42/25 = 168/100 = 1,68

9/5 =\(\dfrac{90}{50}=1,8\)

2/25 =\(\dfrac{20}{250}=0,08\)

23/8 =\(\dfrac{23}{8}=2,875\)

76/4 =\(\dfrac{76}{40}=\dfrac{19}{10}\)

42/25 =\(\dfrac{420}{250}=1,68\)

=-3720

đồ bấm máy tính ko chấp

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31

+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+4

7+48+49+50-999-888-777-666-555-444-333-222-111= -3720

1.

a) \(125+80+375+220\)

\(=\left(125+375\right)+\left(80+220\right)\)

\(=500+300\)

\(=800\)

b) \(25.11.8.4.125\)

\(=\left(25.4\right).\left(8.125\right).11\)

\(=100.1000.11\)

\(=1100000\)

c) \(18.74+18.27-18\)

\(=18.\left(74+27-1\right)\)

\(=18.100\)

\(=1800\)

d) \(75.23+75.77-500\)

\(=75.\left(23+77\right)-500\)

\(=75.100-500\)

\(=7500-500\)

\(=7000\)

e) \(150:\left[25.\left(18-4^2\right)\right]\)

\(=150:\left[25.\left(18-16\right)\right]\)

\(=150:\left[25.2\right]\)

\(=150:50\)

\(=3\)

f) \(125.23.2.8.50\)

\(=\left(125.8\right).\left(2.50\right).23\)

\(=1000.100.23\)

\(=2300000\)

g) \(235+88+165+12\)

\(=\left(235+165\right)+\left(88+12\right)\)

\(=400+100\)

\(=500\)

h) \(71.32+71.68-1100\)

\(=71.\left(32+68\right)-1100\)

\(=71.100-1100\)

\(=7100-1100\)

\(=6000\)

i) \(6^7:6^6+4^3.2-24^0\)

\(=6+64.2-1\)

\(=6+128-1\)

\(=133\)

j) \(546-6.\left[158:\left(30+7^2\right)\right]\)

\(=546-6.\left[158:\left(30+49\right)\right]\)

\(=546-6.\left[158:79\right]\)

\(=546-6.2\)

\(=546-12\)

\(=534\)

k) \(268+147+132+253\)

\(=\left(268+132\right)+\left(147+253\right)\)

\(=400+400\)

\(=800\)

2. 

a) \(7x=707\)

\(x=707:7\)

\(x=101\)

b) \(6x+5=47\)

\(6x=47-5\)

\(6x=42\)

\(x=42:6\)

\(x=7\)

c) \(35:\left(x+1\right)=7\)

\(x+1=35:7\)

\(x+1=5\)

\(x=5-1\)

\(x=4\)

d) \(12+\left(29-3x\right)=35\)

\(29-3x=35-12\)

\(29-3x=23\)

\(3x=29-23\)

\(3x=6\)

\(x=6:3\)

\(x=2\)

e) \(2.4^x+10^1=138\)

\(2.4^x=138-10\)

\(2.4^x=128\)

\(4^x=128:2\)

\(4^x=64=4^3\)

\(\Rightarrow x=3\)

f) \(7x=140\)

\(x=140:7\)

\(x=20\)

g) \(7\left(15-x\right)+14=84\)

\(7\left(15-x\right)=84-14\)

\(7\left(15-x\right)=70\)

\(15-x=70:7\)

\(15-x=10\)

\(x=15-10\)

\(x=5\)

h) \(3^x.5-15=390\)

\(3^x.5=390+15\)

\(3^x.5=405\)

\(3^x=405:5\)

\(3^x=81=3^4\)

\(\Rightarrow x=4\)

3.

Ta có:

\(\Rightarrow n+11⋮n+1\)

\(\Rightarrow n+1+10⋮n+1\)

\(\Rightarrow10⋮n+1\) hay \(n+1\inƯ\left(10\right)=\left\{-10;-5;-2;-1;1;2;5;10\right\}\)

\(\Rightarrow\) \(n\in\left\{-11;-6;-3;-2;0;1;4;9\right\}\)

Vì \(n\in N\) nên \(n\in\left\{0;1;4;9\right\}\)

1) (-25).8.(-4).(-125)

= [(-25).4].[(-125).8]

=(-100).(-1000)

=100000

2)30.(5-10)

=30.5-30.10

=30.5-300

=150-300

=(-150)

3) 43.(53-81)+53.(81-43)

=43.53-43.81+53.81-53.43

=(43.53-53.43)+(43.81-53.81)

=0+81.(43-53)

=(-810)

4) Mk chưa biết làm nha

1) (-25).8.(-4).(-125)

= [ (-25) . (-4) ] . [ 8 . (-125) ]

= 100 . (-1000)

= -100 000

2) 30.(-5-10)

= 30 . (-15)

= -450

3) 43.(53-81)+53.(81-43)

= 43 . 53 - 43 . 81 + 53 . 81 - 53.43

= -43 . 81 + 53 . 81

= 81 . ( -43 + 53)

= 81 . 10

= 810

4) (-6)².(-17)+23.(-36)-72.30

= 36 . (-17) + 23 . (-36) - 72. 30

= (-36) . 17 + 23 . (-36) - 72 . 30

= (-36) . ( 17 + 23 ) - 72 . 30

= (-36) . 40 - 72.30

=  (-1440 )- 2160

= -3600

# HOK TỐT #

1) (-25).8.(-4).(-125)

=[-25.(-4)].[8.(-125)]

=100.(-1000)

=-100000

2) 30.(-5-10)

=30.(-15)

=-450

3) 43.(53-81)+53.(81-43)

=43.(-28)+53.38

=-1176+2014

=838

4) (-6)².(-17)+23.(-36)-72.30

=36.(-17)+23.(-36)-72.30

=36.(-17)+(-23).36-72.30

=36.[-17+(-23)]-72.30

=36.(-40)-72.30

=-1440-2160

=-3600