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bạn có thể giải chi tiết giúp mình được ko 

\(A=2,53\times17+17,67\times15+2,53\times83+17,67\times85\)

\(A=2,53\times17+2,53\times83+17,67\times15+17,67\times85\)

\(A=2,53\times\left(17+83\right)+17,67\times\left(15+85\right)\)

\(A=2,53\times100+17,67\times100\)

\(A=253+1767\)

\(A=2020\)

Tìm y biết y : 10 + y × 3,9 =4,8

=1358 x (15+85)+358x(590-490)

=1358x100+358x100

=100x(1358+358)

=100x1716

=171600

= 1358 x ( 15 + 85) + 358 x ( 590 - 490)

= 1358 x 100 + 358 x 100

= 100 x ( 1358 + 358 ) 

= 100 x 1716 = 171600

85 x 72,5 + 15 x 72,5

= 72,5 x ( 85 + 15 )

= 72,5 x 100 

= 72,500

= 72,5 x (85+15)

=72,5 x100

= 7250

k mk nhoa

3 x 15 + 21 x 15 + 85 x 5

= 45 + 315 + 425

= 785

15 - 30 + 40 

= 25

21 + 19 - 50 + 10

= 0

\(\dfrac{1}{5}-\dfrac{1}{4}+2\)

\(=-\dfrac{1}{20}+2\)

\(=\dfrac{39}{20}\)

\(\left(\dfrac{1}{4}+\dfrac{1}{6}\right)\times\left(\dfrac{1}{2}-\dfrac{1}{4}\right)\)

\(=\dfrac{5}{12}\times\dfrac{1}{4}\)

\(=\dfrac{5}{12}\times\dfrac{3}{12}\)

\(=\dfrac{5}{48}\)

\(\dfrac{1}{10}+\dfrac{1}{5}-\dfrac{3}{4}\)

\(=-\dfrac{9}{20}\)

\(3\times15+21\times15+85\times5\\ =15\times\left(3+21\right)+425\\ =15\times24+425\\ =360+425\\ =785\)

\(15-30+40\\ =\left(15+40\right)-30\\ =55-30\\ =25\)

\(21+19-50+10\\ =\left(21+19\right)-\left(50-10\right)\\ =40-40\\ =0\)

\(\dfrac{1}{5}-\dfrac{1}{4}+2\)

\(=\dfrac{4}{20}-\dfrac{5}{20}+\dfrac{40}{20}\)

\(=\dfrac{\left(4+40\right)}{20}-\dfrac{5}{20}\)

\(=\dfrac{44}{20}-\dfrac{5}{20}\)

\(=\dfrac{39}{20}\)

\(\left(\dfrac{1}{4}+\dfrac{1}{6}\right)\times\left(\dfrac{1}{2}-\dfrac{1}{4}\right)\)

\(=\dfrac{5}{12}\times\dfrac{1}{4}\)

\(=\dfrac{5}{48}\)

\(\dfrac{1}{10}+\dfrac{1}{5}-\dfrac{3}{4}\)

\(=\dfrac{2}{20}+\dfrac{4}{20}-\dfrac{15}{20}\)

\(=\dfrac{6}{20}-\dfrac{15}{20}\)

\(=-\dfrac{9}{20}\)

25x187+187x73+817x1+817x1

 = 187x(25+73+1+1)

= 187x100

=18700

25 × 187 + 187 × 73 + 817 + 817 

= 25 × 187 + 187 × 73 +187+187+1260

= 187 x ( 25+73+1+1) + 1260

= 187 x 100 + 1260

= 18700 + 1260

= 19960

chúc bn học tốt 

8,17 : 0,5 + 817/100 x 7 + 8,17 : 0,25 + 8,17 + 81,7 x 0,1 : 0,2 + 8,17

= 8,17 x 2 + 8,17 x 7 + 8,17 x 4 + 8,17 x 1 + 81,7 : 10 x 5 + 8,17 x 1

= 8,17 x 2 + 8,17 x 7 + 8,17 x 4 + 8,17 x 1 + 8,17 x 5 + 8,17 x 1

= 8,17 x (2 + 7 + 4 + 1 + 5 + 1)

= 8,17 x 20

= 163,4

a , 12640

b , - 29493

a) = 136 + 16 * ( 68 + 212 )

    = 152 * 280

    = 42560

b) = 43 * 85 - 81 + 85 * 81 - 430 

    = ( 85 - 85 ) + (81 - 81) * 430 + 43

    =       0       +      0       *      473

    = 0

nhớ k nha

= ( 1277 + 12.74 ) x ( 85 + 25 ) -  1874 x 10

=  1289.74 x (110 - 10) - 1874

= 128974 - 1874

= 127100 

1277 x 85 + 12,74 x 25 - 1874 x 10 

= ( 1277 + 12,74 ) x ( 85 + 25 ) - 1874 x10

= 1289,74 x ( 110 - 10 ) -1874

=128974 - 1874

=127100Thục Hiền 2005