53 .39 + 47 . 39 - 53 . 21 - 47 .21 tính nhanh
Tính nhanh
53*39+47*39-53*21-47*21
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
tính nhanh
53 + 39 + 47 x 39 - 53 x 21 - 47 x 21
Tính nhanh
53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
tính nhanh 210+47*4+16*47
Tính nhanh
a) 78*31+78*24+78*17+22*72
b) 53*39 +47*39-53*21-47*21
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
Tính nhanh
a) 491 x (267+53) - 491 x ( 153 + 67 )
b) 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
a) 491 x (267+53) - 491 x ( 153 + 67 )
=491x<(267+53) - (153+67)>
=491x<300-200>
=491x100
=49100
b) 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
=53x(39-21) - 47x(39-21)
=53x18-47x18
=18x(53-47)
=18x6
=108
bạn ơi cho mình sửa phần b) nha
b) 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
=53x(39-21) + 47x(39-21)
=53x18+47x18
=18x(53+47)
=18x100
=1800
a) 491×(267+53)-491×(153+67)=491×320-490×220=491×(320-220)=491×100=49100.
b) 53×39+47×39-53×21-47×21=(53×39-53×21)+(47×39-47×21)=[53×(39-21)]+[47×(39-21)]=53×18+47×18=(53+47)×18=100×18=1800.
tính nhanh
53* 39+47*39-53*21-47*21
2*53*12+4*6*87-3*8*40
5*7*77-7*60+49*25-15*42
53x39+47x39-53x21-47x21
=39x ( 53+47) - 21x(53+47)
=39 x100 - 21x100
= 100x(39-21)
=100x18
=1800
2x53x12 +4x6x87 - 3x8x40
= (2x12)x53 + (4x16)x87 - (3x8) x40
= 24x53 + 24x87 + 24x40
= 24( 53+87+40)
= 24x180
=4320
a,53*39+47*39-53*21-47*21
=39*[53+47]-21*[53+47]
=39*100-21*100
=3900-2100
=1800
b,2*53*12+4*6*87-3*8*40
=[2*12]*53+[4*6]*87-[3*8]*40
=24*53+24*87-24*40
=24*[53+87-40]
=24*100
=2400
tính nhanh a / 166 * ( – 127 + 234 ) – 234 * ( 166 +127 )
b / 53 * 39 + 43 * 39 – 53 * 21 – 47 * 21
a) 166.(-127)+166.234+(-234).166-234.127
166.(-234+234)+127.(-166-234)
=0+127.(-400)
=-50800
b) 53.39+43.39-53.21-47.21
=39.(53+43)+(-21).(53+47)
=39.96+(-21).100
=-1644
k cho minh
tính nhanh:
a:53*39+47*39-53*21-47*21
b:2*53*12+4*6*87-3*8*40
c:5*7*77-7*60+49*25-15*42
53 . 39 + 47 . 39 - 53 . 21 - 47 .21
= 39 . ( 53 + 47 ) - 21 . ( 53 + 47 ) = 39 . 100 - 21 . 100 = 100 . ( 39 - 21 ) = 100 . 18 = 1800