108 *(47+23)-8 *(23+47)=
c tính nhanh:
47*48-47*47-24-23+2046/2+4+8...+512+1024
A = \(\dfrac{47\times48-47\times47-24-23+2046}{2+4+8+..+512+1024}\)
Đặt tử số là B, mẫu số là C thì
B = 47\(\times\)48 - 47 \(\times\) 47 - 24 -23+2046vàC = 2 + 4 + 8 +....+ 512 + 1024
B = 47 \(\times\) 48 - 47 \(\times\) 47 - 24 - 23 + 2046
B= 47 \(\times\) 48 - 47 \(\times\) 47 - ( 24 + 23) + 2046
B = 47 \(\times\) 48 - 47 \(\times\) 47 - 47 + 2046
B = 47 \(\times\) 48 - 47 \(\times\) 47 - 47 \(\times\) 1 + 2046
B = 47 \(\times\) ( 48 - 47 - 1) + 2046
B = 47 \(\times\) 0 + 2046
B = 2046
C = 2 + 4 + 8+ ....+ 512 +1024
C \(\times\) 2 = 4 + 8 +.....+ 512 + 1024 + 2048
C \(\times\) 2 - C = 2048 - 2
C \(\times\) ( 2 - 1) = 2046
C = 2046
A = \(\dfrac{B}{C}\) = \(\dfrac{2046}{2046}\) = 1
Tính nhanh:
9) 1 . 2 . 3 . ..... 9 - 1.2.3 . ..... 8 - 1.2.3 . .... 8\(^2\)
10) 47 . ( 23 + 50 ) - 23 . ( 47 + 50)
7) -29.(85-47)-85.(47-29)
8) -15.(23-29)+23-(15-29)
9) -13.(55-29)+23.(15-29)
13)-10.(2+4)-5.(4-3)
-29.(85-47)-85.(47-29)
=-29.38-85.18
=-1102-1503
=-2605
-15.(23-29)+23-(15-29)
=-15.(-6)+23-(-14)
=90+23+14
=113+14
=127
-13.(55-29)+23.(15-29)
=-13.26+23.(-14)
=-338+(-322)
=-660
-10.(2+4)-5.(4-3)
=-10.6-5.1
=-60-5
=-65
(23 . 97 +8 . 75 -- 47 . 23) ÷102
GIÚP EM NHANH VỚI Ạ
`#3107.101107`
\(\left[2^3\cdot97+8\cdot75-\left(-47\right)\cdot2^3\right]\div10^2\)
\(=\left(2^3\cdot97+2^3\cdot75+47\cdot2^3\right)\div10^2\)
\(=\left[2^3\cdot\left(97+75-47\right)\right]\div10^2\)
\(=\left(2^3\cdot125\right)\div10^2\)
\(=\left(2^3\cdot5^3\right)\div10^2\)
\(=\left(5\cdot2\right)^3\div10^2\)
\(=10^3\div10^2\)
\(=10\)
\(\left(2^3.97+8.75-47.2^3\right):10^2\\ =\left[\left(97-47+75\right).2^3\right]:100\\ =\left[125.8\right]:100\\ =1000:100=10\)
47.(23+50)-23.(47-50)
47.(23+50)-23.(47-50)=
47.73-23.-3 =
1081-23.-3 =
1058-3 =
1055
47.(23+50)-23.(47-50)
=(47.73)-23.(-3)
=3431-(-69)
=3431+69
=3500
tính hợp lí
a)29.(85-47)+85.(47-29)
b)47.(23+50)-23.(47+50)
a) 29.(85-47)+85.(47-29)= 29.85-29.47+85.47-85.29
=(29.85-85.29) -29.47+85.47
=0-29.47+85.47
= -29.47+85.47
= (-29+85).47
=56.47
= 2632
b)47.(23+50)-23.(47+50)= 47.23+47.50-23.47+23.50
=(47.23-23.47)+47.50+23.50
=0+47.50+23.50
=47.50+23.50
=(47+23).50
=70.50
=3500
tích ^.^ ~
a) 29.(85-47)+85(47-29)
=29.38+85.18
=1102+1520
=2622
b)47.(23+50)-23.(47+50)
=47.73-23.97
=3431-2231
=1200
k mình nha...^_^...kb nữa... thanks
-33.(23-47)-23.(47-33)
-33 . ( 32 - 47 ) - 23 . ( 47 - 33 )
= -33 . (-15) -23 . 14
= 495 - 322
= 173
tinh nhanh 47.(23+50)-23.(47+50)
dễ vồn ..
bằng 1200 bạn ak .. check mk nhé
47 x (23+50)-23x(47+50)
=47 x 73 - 23 x 97
=(97-47)x(73-23)
=50 x 50
=2500
mình sai rùi!!!
ủng hộ nha
Cam on cau tra loi cua cac ban. Ai biet cach lam nho giup minh nhe,minh se h cho
tính :
a, ( 512 - 47 ) - ( 14 - 108 ) - ( -57 + 41 )
b, -(-68 + 15 + 52 ) + ( -41 + 27 + 13 ) - ( 23 - 42 + 34 )
mk cần gấp mong các bạn giúp mk vs nhé
a.
=512-47-14+108+57-41
=(512+108)+(57-47)-(14+41)
=620+10-50
=560