Bài 2b,54 x 47 - 47 x 53 - 20 - 27 Bài 2c, 10000 - 47 x 72 - 47 x 28
bài 7:tính nhanh
a (145 x 99+145)-(143 x 102-143) b,54 x 47 - 47 x 53 - 20 -27
c, 10000 - 47 x 72 - 47 x 28 d, 3457 - 27 x 48 - 48 x 73 + 6543
a) \(\left(145\times99+145\right)-\left(143\times102-143\right)\)
\(=\left[145\times\left(99+1\right)\right]-\left[143\times\left(102-1\right)\right]\)
\(=\left(145\times100\right)-\left(143\times101\right)\)
\(=14500-14443\)
\(=57\)
b) \(54\times47-47\times53-20-27\)
\(=47\times\left(54-53\right)-20-27\)
\(=47-20-27\)
\(=0\)
c) \(10000-47\times72-47\times28\)
\(=10000-47\times\left(72+28\right)\)
\(=10000-47\times100\)
\(=10000-4700\)
\(=5300\)
d) \(3457-27\times48-48\times73+6543\)
\(=\left(3457+6543\right)-48\times\left(27+73\right)\)
\(=10000-48\times100\)
\(=10000-4800\)
\(=5200\)
Tính nhanh:
54 x 113 + 45 x 113 + 113
54 x 47 - 47 x 53 - 20 - 27
10000 - 47 x 72 - 47 x 28
(145 x 99 + 145) - (143 x 101 - 143)
1002 x 9 - 18
8 x 427 x 3 + 6 x 573 x 4
2008 x 867 + 2009 x 133
a/ = 113 x ( 54 + 45 + 1 ) = 113 x 100 = 11300
b/ = 47 x ( 54 - 53 ) - 20 - 27 = 47 - 20 - 27 = 0
c/ = 145 x ( 99 + 1 ) - 143 x ( 101 - 1 ) = 145 x 100 - 143 x 100 = 100 x ( 145 - 143 ) = 100 x 2 = 200
d/ = 1002 x 9 - 2 x 9 = 9 x ( 1002 - 2 ) = 9 x 1000 = 9000
e/ = 24 x 427 + 24 x 573 = 24 x ( 427 + 573 ) = 24 x 1000 = 24000
f/ Sửa đề bài là :
2008 x 867 + 2008 x 133 = 2008 x ( 867 + 133 ) = 2008 x 1000 = 2008000
Bài 5*: Tính nhanh:
10000 - 47 x 72 - 47 x 28 3457 - 27 x 48 - 48 x 73 + 6543
=
1000 - 47 . 72 - 47 .28
= 47 . ( 1000 - 72 -28 )
= 47 .0
=0
3457 - 27 . 48 - 48 .73 + 6543
=3457 - 48 . (27 + 73 ) + 6543
= 3457 - 4800 + 6543
= 5200
54 x 47 - 47 x 53 - 20 - 27
54 x 47 - 47 x 53 - 20 - 27
= 54 x 47 - 47 x 53 - 47
= 47 x (54-53-1)
= 47 x 0
= 0
54 x 47 - 47 x 53 - 20 - 27
= 47 x (54 - 53) - 20 - 27
= 47 x 1 - 20 - 27
= 47 - (20 + 27)
= 47 - 47
= 0
10000 - 47 x 72 - 47 x 28
3457-27 x48 -48 x73 + 6543
10000-47x72-47x28
=10000-47x72-47x47-28
=47x(10000-72-28)
=47x0
=0
MIK CHỈ GIẢI DƯỢC PHẦM ĐẦU THUI
SORRY NHÉ
= 47 x (1000 - 72 - 28 )
= 47 x 0
= 0
1000 - 47 . 72 - 47 .28
= 47 . ( 1000 - 72 -28 )
= 47 .0
=0
3457 - 27 . 48 - 48 .73 + 6543
=3457 - 48 . (27 + 73 ) + 6543
= 3457 - 4800 + 6543
= 5200
Tính nhanh
a. 54 x 113 + 45 x 113 + 113
b. 54 x 47 - 47 x 53 - 20 - 27
a. 54 x 113 + 45 x 113 + 113
= 113 x (54 + 45 + 1)
= 113 x 100 = 11300
Vậy giá trị cần tìmlaf: 11300
b. 54 x 47 - 47 x 53 - 20 - 27
= 54 x 47 - 47 x 53 - (20 + 27)
= 54 x 47 - 47 x 53 - 47
= 47 x (54 - 53 - 1)
= 47 x 0 = 0
Vậy giá trị cần tìm là: 0
\(a,54\times113+45\times113+113\\ =113\times\left(54+45+1\right)\\ =113\times100=11300\)
\(b,54\times47-47\times53-20-27\\ =54\times47-47\times53-47\\ =47\times\left(54-53-1\right)\\ =47\times0=0\)
Bài 3: Tính bằng cách thuận tiện
a) 10000 – 47 x 72 – 47 x 28
b) 3457 – 27 x 48 – 48 x 73 + 6543
c) (145 x 99 + 145 ) – ( 143 x 102 – 143 - 143 )
c)(145x99+145)-(143x102-143)
= 145x(99+1)-143x(101-1)
= 145x100-143x100
= (145-143)x100
= 2x100
= 200
Tính nhanh
(145 x 99 + 145 ) - ( 143 x 102 – 143 × 2 ) + 54 x 47 - 47 x 53 - 20 - 27
(145 x 99 + 145 ) - ( 143 x 102 – 143 × 2 ) + 54 x 47 - 47 x 53 - 20 - 27
= 145 × (99 + 1) – 143 × (102 – 2) + 47 × (54 – 53) – (20 + 27)
= 145 × 100 – 143 × 100 + 47 × 1 – 47
= 100 × (145 – 143) + (47 – 47)
= 100 × 2 + 0
= 200
Tính nhanh (145 x 99 + 145 ) - ( 143 x 102 – 143 × 2 ) + 54 x 47 - 47 x 53 - 20 - 27
(145 x 99 + 145 ) - ( 143 x 102 – 143 × 2 ) + 54 x 47 - 47 x 53 - 20 - 27
= 145 × (99 + 1) – 143 × (102 – 2) + 47 × (54 – 53) – (20 + 27)
= 145 × 100 – 143 × 100 + 47 × 1 – 47
= 100 × (145 – 143) + (47 – 47)
= 100 × 2 + 0
= 200