\(1235\text{×}6789\text{×}\left(630-315\text{×}2\right)\)

\(=1235\text{×}6789\text{×}\left(630-630\right)\)

\(=1235\text{×}6789\text{×}0=0\)

\(\left(100+67\right)\text{×}67+\left(200-38\right)\text{×}33\)

\(=167\text{×}67+167\text{×}33\)

\(=167\text{×}\left(67+33\right)\)

\(=167\text{×}100=16700\)

\(72+36\text{×}2+24\text{×}3+18\text{×}4+12\text{×}2+168\)

\(=72+72+72+72+24+168\)

\(=\left(72\text{×}4\right)+24+168=288+24+168=480\)

a) \(1235\times6789\times\left(630-630\right)\)

\(=1235\times6789\times0\)

\(=1235\times0\)

\(=0\)

b) \(167\times67+167\times33\)

\(=167\times\left(67+33\right)\)

\(=167\times100\)

=16700

427 x 234 - 325 x 168 = 99918 - 54600 = 45318

16616 : 67 x 8815 : 43 = 248 x 8815 : 43 = 2186120

67032 : 72 + 258 x 37 = 931 + 9546 = 10477

324 x 127 : 36 + 873 = 2016

a) 570 - 225 - 167 + 67

= 345 - 167 + 67 = 178 + 67 = 245

168 x 2 : 6 x 4 = 336 : 6 x 4 = 56 x 4 = 224

b) 468 : 6 + 61 x 2 = 78 + 122 = 200

5625 - 5000 : (726 : 6 - 113)

= 5000 - 5000 : (121 - 21)

= 5000 - 5000 : 100 = 5000 - 50 = 4950

a) Ta có: \(\dfrac{-11}{15}< \dfrac{x}{15}< \dfrac{-8}{15}\)

nên -11<x<-8

hay \(x\in\left\{-10;-9\right\}\)

b) Ta có: \(\dfrac{3}{7}< \dfrac{x}{21}< \dfrac{2}{3}\)

\(\Leftrightarrow\dfrac{9}{21}< \dfrac{x}{21}< \dfrac{14}{21}\)

Suy ra: 9<x<14

hay \(x\in\left\{10;11;12;13\right\}\)

c) Ta có: \(\dfrac{-67}{21}< \dfrac{x}{168}< \dfrac{-3}{8}\)

nên \(\dfrac{-536}{168}< \dfrac{x}{168}< \dfrac{-63}{168}\)

Suy ra: -536<x<-63

hay \(x\in\left\{-535;-534;...;-64\right\}\)

a)67.153-53.67+712:8

=67.(153-53)+89

=67.100+89

=6789

\(a,67\times153-53\times67+712:8\)

\(=67\times\left(153-53\right)+\left(712:8\right)\)

\(=67\times100+89\)

\(=6700+89\)

\(=6789\)

\(b,168-\left\{5\times\left[143-\left(15-12\right)^2\right]+10\right\}:10\)

\(=168-\left\{5\times\left[143-3^2\right]+10\right\}:10\)

\(=168-\left\{5\times134+10\right\}:10\)

\(=168-\left\{670+10\right\}:10\)

\(=168-680:10\)

\(=168-68\)

\(=100\)

\(c,\left(-13\right)+84+\left(-87\right)+16\)

\(=13+84-87+16\)

\(=\left(13+87\right)-\left(84+16\right)\)

\(=100-100\)

\(=0\)

\(d,9-\left(12-15\right)\)

\(=9-\left(-3\right)\)

\(=12\)

Bài 5:

a: 2x=10

nên x=5

b: x:6=5

nên x=30

\(\frac{23}{5}\)\(=\)\(4\frac{3}{10}\);\(\frac{67}{10}\)\(=\)\(6\frac{7}{10}\);\(\frac{313}{100}\)\(=\)\(3\frac{13}{100}\); \(\frac{168}{11}\)=  \(11\frac{68}{100}\)

                                              mk nha

khùng

23/5=4 và 3/5

67/10=6 và 7/10

313/100=3 và 13/100

168/11=15 và 3/11

570-225-167+67=345-167+67

                        =178+67=245

168x2:6x4=336:6x4=56x4=224

b)468:6+61x2=78+61x2=78+122=200

5625-5000:(726:6-113)=5625-5000:8=5625-625=5000

tick cho minh nha

A.245                       B.200

 224                         5000

a) 570 - 225 - 167 + 67 = 345 - 167 + 67 = 178 + 67 = 245

    168 x 2 : 6 x 4 = 336 :  6 x 4 = 56 x 4 = 224

b) 468 : 6 + 61 x 2 = 78 + 122 = 200

   5625 - 5000 : (726 : 6 - 113) = 5000 - 5000 : (121 - 21) = 5000 - 5000 : 100 = 5000 - 50 = 4950

vì \(x-67=0\Rightarrow x=0\)

x - 67 = 0 + 67

<=> x - 67 = 67

x = 67 - 67

x = 0

nha bn

X - 67 = 0 + 67

      X = 134