53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

= 39 x ( 53 + 47 ) - 21 x ( 53 + 47 ) 

= 39 x 100 - 21 x 100

= 100 x ( 39 - 21 )

= 100 x 18

= 1800

53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

= 39 x ( 53 + 47 ) - 21 x ( 53 + 47 )

= 39 x 100 - 21 x 100

= 100 x ( 39 - 21 )

= 100 x 18

= 1800

ai k mik k lai

53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

= 39 x ( 53 + 47 ) - 21 x ( 53 + 47 ) 

= 39 x 100 - 21 x 100

= 100 x ( 39 - 21 )

= 100 x 18

= 1800

53 .39 + 47 . 39 - 53 . 21 - 47 .21

= (53 + 47) . 39 - (53 + 47) . 21

= 100 . 39 - 100 . 21

= 100 . (39 - 21)

= 100 . 18

= 1800

53 . 39 + 47 . 39-53 .21 - 47 . 21

= 39. (53 + 47 ) - 21. ( 53 -47)

=39 . 100 - 21 . 6

= 3900 -126

=3774

\(53.39+47.39-53.21-47.21\)

\(=39.\left(47+53\right)-\left(53-47\right).21\)

\(=39.100-6.21\)

\(=3.13.100-2.3.21\)

\(=3.\left(1300-42\right)\)

\(=3.1258\)

\(=3774\)

=-175 bạn ạ

-175 nhé

39. ( 47+ 53 )-21

= 3900-21

= 3811

tính nhanh 210+47*4+16*47

53 x 39 + 47 x 39 - 53 x 21 - 47 x 21

42 * 53 + 47 * 156 + 47 * 114=2226+7332+5358=14926

k cho mik nha!

\(42.53+47.156-47.144\)

\(=42.53+47.\left(156-114\right)\)

\(=42.53+47.42\)

\(=42.\left(53+47\right)\)

\(=42.100\)

\(=4200\)

Bạn sai đề rồi nhé !!!

chịu

gg

135*57+135*86-35*143= 135 (57+86)-35*143=135*143-35*143=143 (135-35)=143*100=14300

91*47+49*53-18*47+24*53=(91*47-18*47)+(49*53+24*53)=47*(91-18)+53*(49+24)=47*73+53*73=73*(47+53)=73*100=7300

a, 

\(135\cdot57+135\cdot86-35\cdot143\)  

\(=135\cdot\left(57+86\right)-35\cdot143\)  

\(=135\cdot143-35\cdot143\) 

\(=143\cdot\left(135-35\right)\) 

\(=135\cdot100\) 

\(=13500\) 

b, 

\(91\cdot47+49\cdot53-18\cdot47+24\cdot53\) 

\(=91\cdot47-18\cdot47+49\cdot53+24\cdot53\) 

\(=47\cdot\left(91-18\right)+53\cdot\left(49+24\right)\) 

\(=47\cdot73+53\cdot73\) 

\(=73\cdot\left(47+53\right)\) 

\(=73\cdot100\) 

\(=7300\)   

b, 53.39 + 47.39 - 53.21 - 47.21
  = 39( 53 + 47) - 21  53 + 47)
  = 39.100 - 21.100
  = 100(39 - 21) 
   = 100. 18
   = 1800  

bấm cho mình đúng nha ^_^

a)=78.(31+24+17)+22.72

=72.(78+22)

=72.100

=7200

b)=39.(53+47)-21.(53+47)

=100.(39-21)

=100.18

=1800

Tính nhanh 

a) 78*31+78*24+78*17+22*72

b) 53*39 +47*39-53*21-47*21

Đáp án: A

879 . 2a + 879 . 5a + 879 . 3a = 879. (2a +5a +3a) = 879.10a=8790a

Đáp án cần chọn là: A

Ta có 53+25+47+75=(53+47)+(25+75)=100+100=200