\(=234.\left(135-35\right)\)

\(=234.100\)

\(=23400\)

 Tiên Nguyễn ngọc ơi, cậu trả lời rõ rằng hơn đượ ko

bằng 23400 nha bạn

\(\dfrac{4}{5}\times\left(\dfrac{5}{4}-\dfrac{5}{7}\right)\)

\(=\dfrac{4}{5}\times\left(\dfrac{35}{28}-\dfrac{20}{28}\right)\)

\(=\dfrac{4}{5}\times\dfrac{15}{28}\)

\(=\dfrac{3}{7}\)

__

\(\dfrac{5}{8}\times\dfrac{9}{7}+\dfrac{5}{8}\times\dfrac{5}{7}\)

\(=\dfrac{5}{8}\times\left(\dfrac{9}{7}+\dfrac{5}{7}\right)\)

\(=\dfrac{5}{8}\times2=\dfrac{10}{8}=\dfrac{5}{4}\)

\(\dfrac{5}{12}+\dfrac{8}{12}+\dfrac{7}{12}+\dfrac{4}{12}=\dfrac{5+8+7+4}{12}=\dfrac{24}{12}=2\)

sai

nhầm đúng

a = 2013

b=2014

câu 1:

=20,13 x 100 + 20,13 x 4 - 20,13 x 4

=2013

câu 2

=20,14 x 100 - 20,14 x 0,1 + 20,14 x 0,1

=2014

a) 21/11 x 22/17 x 68/63 = 21 x 22 x 68/11 x 17 x 63 = 1 x 2 x4/1 x 1 x 3= 8/3

b) kết quả là 2/10 = 1/5

         phần b làm như phần a

a) = \(\frac{21\cdot22\cdot68}{11\cdot17\cdot63}\)=\(\frac{1\cdot2\cdot4}{2\cdot1\cdot3}\)=\(\frac{4}{3}\)

b) = \(\frac{5\cdot7\cdot26}{14\cdot13\cdot25}\)=\(\frac{1\cdot1\cdot2}{2\cdot1\cdot5}\)=\(\frac{1}{5}\)

\(\frac{21}{11}\times\frac{22}{17}\times\frac{68}{63}\)

\(=\frac{21}{1}\times\frac{2}{1}\times\frac{4}{63}\)

\(=42\times\frac{4}{63}\)

\(=\frac{168}{63}\)

a.         63x45+63x55 

   =63x(45+55) 

   =63x100 

   =6300 

b.         546,43 + 64 x 546,43 + 36 

     KO tính nhanh dc nha

          (chắc đề sai)

63 . 45 + 63 . 55...........................

= 63 ( 45 + 55 )..........................

= 63 . 100 = 6300..............

63 x 45 + 63 x 55 = 63 x ( 45 + 55)               

                             = 63 x 100

                             = 6300                      

   999 x 4,26 - 333 x 2,78

= 333 x 2 x 4,26 - 333 x 2,78

= 333 x ( 2 x 4,26 - 2,78 )

= 333 x 5,74

= 1911,42

   999x4,26-333x2,78

=333x3x4,26-333x2,78

=333x12,78-333x2,78

=333x(12,78-2,78)

=333x10

=3330

\(419:\left(8\times8\times4,18+0,17\times2,5+2,09\times2\times36+0,23\times2,5\right)\)

\(=419:\left(64\times4,18+0,17\times2,5+4,18\times36+0,23\times2,5\right)\)

\(=419:\left[\left(64+36\right)\times4,18+\left(0,17+0,23\right)\times2,5\right]\)

\(=419:\left[100\times4,18+0,4\times2,5\right]\)

\(=419:\left[418+1\right]\)

\(=419:419\)

\(=1\)

\(=\dfrac{419}{64\cdot4.18+0,17\cdot2,5+2,09\cdot72+0,23\cdot2,5}\)

\(=\dfrac{419}{0,4\cdot2,5+64\cdot4,18+2,09\cdot72}\)

\(=\dfrac{419}{1+418}=1\)