tinh nhanh
12*53+5*172-53*84
12 . 53 + 53 . 172 - 53 . 84 Tinh nhanh
12.53+53.172 - 53.84
= 53.(12+172 - 84)
= 53.100
= 5300
\(12.53+53.172-53.84\)
\(=53.\left(12+172\right)-53.84=53.184-53.84\)
\(=53.\left(184-84\right)=53.100=53.10^2\)
\(=53.10.10=530.10\)
\(=5300\)
12 . 53 + 53 . 172 - 53 . 84
= 53 . ( 12+172-84 )
= 53 . 100
= 5300
tinh nhanh
a, 39*49-39*17 b,12*53+53*172-53*84
c,17+18+19+99 d, 23+25+49
e,46-45+44-43
a, 39*49-39*17
= 39 (49 - 17)
= 39 * 32
= 1248
b,12*53+53*172-53*84
= 53 (12 + 172 -84)
= 53 * 100
= 5300
c,17+18+19+99
= 17 + 17 +1 + 17 +2 + 99
= 3 * 17 + (1+ 99) + 2
= 151 +2
= 153
d, 23+25+49
= 48 + 49
= 97
e,46-45+44-43
= (46 + 44) + (-45 -43)
= 88 + (-88)
= 0
Tinh bang cách hợp lý nhất
A,39×8+60×2+21×8 b,12×53+53×172-53×84
C,35×34+35×86+65×75+65×67+65×45
D,36×28+36×82+64×69+64×41
a, 39 . 8 + 60 . 2 + 21 . 8
= 39 . 8 + 15 . 4 . 2 + 21 . 8
= 39 . 8 + 15 . 8 + 21 . 8
= 8 . ( 39 + 15 + 21 )
= 8 . 75
= 600
b, 12 . 53 + 53 . 172 - 53 . 84
= 53 . ( 12 + 172 - 84 )
= 53 . 100
= 5300
c, 35 . 34 + 35 . 86 + 65 . 75 + 65. 67 + 65.45
= 35 . ( 34 + 86 ) + 65 . ( 75 + 67 + 45 )
= 35 . 120 + 65 . 187
= 4200 + 12155
= 16355
d, 36 . 28 + 36 . 82 + 64 . 69 + 64 . 41
= 36 . ( 28 + 82 ) + 64 . ( 69 + 41 )
= 36 . 110 + 64 . 110
= 110 . ( 36 + 64 )
= 110 . 100
= 11000
a, 39 . 8 + 60 . 2 + 21 . 8
= 39 . 8 + 15 . 4 . 2 + 21 . 8
= 39 . 8 + 15 . 8 + 21 . 8
= 8 . ( 39 + 15 + 21 )
= 8 . 75
= 600
b, 12 . 53 + 53 . 172 - 53 . 84
= 53 . ( 12 + 172 - 84 )
= 53 . 100
= 5300
c, 35 . 34 + 35 . 86 + 65 . 75 + 65. 67 + 65.45
= 35 . ( 34 + 86 ) + 65 . ( 75 + 67 + 45 )
= 35 . 120 + 65 . 187
= 4200 + 12155
= 16355
d, 36 . 28 + 36 . 82 + 64 . 69 + 64 . 41
= 36 . ( 28 + 82 ) + 64 . ( 69 + 41 )
= 36 . 110 + 64 . 110
= 110 . ( 36 + 64 )
= 110 . 100
= 11000
Mn có thể giúp:
Đề : tính nhanh
53 x 172 - 53 x 84 + 12 x 53 = ?
Khó qué giúp đi mn !!!
53 x 172 - 53 x 84 + 12 x 53
= 53 x (172 - 84 + 12)
= 53 x 100
= 5300.
Nếu đúng xin like
53.172-53.84+12.53
= 53.(172-84+12)
=53.100
=5300
a) 463 + 318 - 137 + 55
b) 589 + 424 - 289 + 276 + 55
c) 12 . 53 + 53 . 172 - 53 . 84
d) 39 . 8 + 60 . 2 + 21 . 8
e) 14 . 10 . 32 : ( 300 + 20 )
só đó là
a)699
b)1055
c)5300
d)14
bn ủng hộ
mình nhé
Bài 7: Tính nhanh
c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12 d) (1200 + 60) : 12
e) 12.53 + 53. 172 – 53. 84 g) (2100 – 42) : 21
h) 39.8 + 60.2 + 21.8 i) 36.28 + 36.82 + 64.69 + 64.41
k) 32. 47 + 32. 53 l) 37.7 + 80.3 +43.7
m) 113.38 + 113.62 + 87.62 + 87.38 n) 123.456 + 456.321 –256.444
p) 43.37 + 93.43 + 57.61 + 69.57 q) 38. 63 + 37. 38
r) 35.34 +35.38 + 65.75 + 65.45
c, 3.25.8 + 4.37.6 + 2.38.12
= (3.8).25 + (4.6).37 + (2.12).38
= 24.25 + 24.37 + 24.38
= 24.(25 + 37 + 38)
= 24.100
= 2400
d, (1200 + 60):12
= 1200: 12 + 60: 12
= 100 + 5
= 105
e, 12.53 + 53.172 - 53.84
= 53.(12 + 172 - 84)
= 153.( 184 - 84)
= 153. 100
= 15300
Bài 7: Tính nhanh
c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12 d) (1200 + 60) : 12
e) 12.53 + 53. 172 – 53. 84 g) (2100 – 42) : 21
h) 39.8 + 60.2 + 21.8 i) 36.28 + 36.82 + 64.69 + 64.41
c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12
= 24. 25 + 24 . 37 + 24.38
= 24.(25 +37+ 38)
= 24. 100 = 2400
d) (1200 + 60) : 12
= 1200 : 12 + 60: 12
= 100 + 5 = 105
e) 12.53 + 53. 172 – 53. 84
= 53 . ( 12+ 172 - 84)
= 53 . 100 = 5300
g) (2100 – 42) : 21
= 2100 : 21 - 42: 21
= 100 - 2 = 98
h) 39.8 + 60.2 + 21.8
= 39 .8 + 60 . 2 + 21 . 8
= 8.( 39 + 21) + 120
= 8 . 60 + 120 = 480 + 120 = 600
i) 36.28 + 36.82 + 64.69 + 64.41
= 36.(28 + 82) + 64.( 69 + 41) = 36. 110 + 64 . 110 = 110.( 36 + 64) =110. 100 = 11000
Nhớ tick nha em chị làm mãi mới được đấy
Bài 7: Tính nhanh
a) 37. 38 + 62. 37 b) 28. 64 + 28. 36
c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12 d) (1200 + 60) : 12
e) 12.53 + 53. 172 – 53. 84 g) (2100 – 42) : 21
h) 39.8 + 60.2 + 21.8 i) 36.28 + 36.82 + 64.69 + 64.41
k) 32. 47 + 32. 53 l) 37.7 + 80.3 +43.7
m) 113.38 + 113.62 + 87.62 + 87.38 n) 123.456 + 456.321 –256
a. 37. 38 + 62. 37
= 37 . (38 + 62)
= 37 . 100
= 3700
b. 28. 64 + 28. 36
= 28 . (64 + 36)
= 28 . 100
= 2800
c. 3. 25. 8 + 4. 37. 6 + 2. 38. 12
= 3 . 8 . 25 + 4 . 6 . 37 + 12 . 2 . 38
= 24 . 25 + 24 . 37 + 24 . 38
= 24 . (25 + 37 + 38)
= 24 . 100
= 2400
Tính hợp lí
A.35 x 34 + 35 x 38 + 65 x 75 + 65 x 45
B. 12x 53 + 53 x 172 - 53 x 84
C. 35 x 28 + 36 x 82 + 64 x 69 + 64 x 41
D. A = 1+2+3+...+100
E. B =17+19+...+101+103
G. D= 3x (12+13+14+15) + 3x(8+7+6+5)
A.35 x 34 + 35 x 38 + 65 x 75 + 65 x 45
Câu này không tính hợp lí được
B. 12x 53 + 53 x 172 - 53 x 84
= 53 x (12 + 172 - 84)
= 53 x 100
= 5300
C. 36 x 28 + 36 x 82 + 64 x 69 + 64 x 41
= 36 x (28+82) + 64 x (69+41)
= 36 x 110 + 64 x 110
= (36+64) x 110
= 100 x 110
= 11 000
D. A = 1+2+3+...+100
= (1+ 100) x 50
= 101 x 50
= 5050
E. B =17+19+...+101+103
= (103 +17) x [(103 - 17):2 + 1]
= 120 x 44
=5280
G. D= 3x (12+13+14+15) + 3x(8+7+6+5)
= 3 x (5+6+7+8+12+13+14+15)
= 3 x (20 x 4)
= 3 x 80
=240
a) 10320
b) 5300
c) 11000
d) 5050
e) 2460
g) 240