12 : 3 = 4 x 4 = 16

20 x 3 = 60

90 : 1 = 90

123 - 123 = 0

10 x 9 = 90 : 9 = 10

12 - 9 = 3 x 9 = 27

23 - 5 = 18

123 + 12 = 135

1000 - 200 = 800

333 - 111 = 222

\(20.3=60\)

\(90.1=90\)

\(123-123=0\)

\(10.9=\frac{810}{9}=90\)

\(23-5=15\)

\(123+12=135\)

\(1000-200=800\)

\(333-111=222\)

123 + 1 x 2 - x = 90

123 + 2 - x       = 90

125 - x              = 90

         x              = 125 - 90

         x               = 35

123 + 1 x 2 - x = 90

123 +   2    - x = 90

   125       -   x = 90

                   x = 125 - 90

                   x =     35

123 + 123 x 9 + 123 x 90

= 123 x (90 + 9 + 1)

= 123 x 100

= 12300

123 + 123 x 9 + 123 x 90 = 1443

tk mk vs nha !!!!!!

123 + 123 x 9 + 123 x 90

= 123 x ( 90 + 9 + 1 )

= 123 x 100

= 12300

Ai tk mình mình tk lại

(123 456 x 2) + 12 + 123 - 1234 + 123 - 12 345 = 233591

kq ra 233591

đáp án là : 233591

12 x X = 123 x 123 + 409

12 x X = 15129 + 409

12 x X = 15538

X = 15538 : 12

X = \(\dfrac{7769}{6}\)

\(12.X=123.123+409\)

\(12.X=15129+409\)

\(12.X=15538\)

\(X=15538:12\)

\(X=\dfrac{7769}{6}\)

Vậy \(X=\dfrac{7769}{6}\)

Ghi chú 12 . X = 12 x X

7769/6

\(a,123\times54+27\times123-12\times123+123\times31\)

\(=123\times\left(54+27-12+31\right)\)

\(=123\times100\)

\(=12300\)

\(b,\dfrac{121}{27}\times\dfrac{54}{11}< n< \dfrac{100}{21}:\dfrac{25}{126}\)

\(22< n< \dfrac{100}{21}\times\dfrac{126}{25}\)

\(22< n< 24\)

Vì \(23>22\) và \(23< 24\) nên \(n=23\)

a, 123x(54+27-12+31)

=123x100

=12300

a123x54+27x123-12x123+123x31

=123:54+27:123-12:123+123:31

=6642+27:123-12:123+123:31

=6642+3321-12:123+123:31

=6642+3321-1476+123:31

=6642+3321-1476+3813

=12300

b,121/27x54/11<n>100/21:25/126

=22<n>24

n=23

\(=12\left(123+4567+5310\right)=120000\)

a.12x123+3x4567+6x5310x2

1476+13701+31860x2

47037x2=94074

12 x 123 + 3 x 4567 x 4 + 6 x 5310 x 2

= (123 + 4567 + 5310) x (12 + 3 + 4 + 6 + 2)

= 10000 x 27

= 270000.

Hơi hack não chút nhưng chắc mình làm đúng rồi...