Tính nhanh:
A=123.(123+154)+77*2
tính nhanh:
123.(123+154)+77*2
tính nhanh:
123.(123+154)+77*2
A=123^2 + 54.123 + 77^2
= 123^2 + 2.123.77 + 77^2 - (154-54).123
= (123+77)^2 - 100.123
= 200^2 -12300
= 40000-12300
= 27700.
Tính nhanh:123*154-24*123-123*30.Nhanh nha mọi người
123*154-24*123-123*30.
=123.(154-24-30)
=123.100=12300
k mk nhé ,thank you nhìu
\(123.154-24.123-123.30\)
\(=123.\left(154-24-30\right)\)
\(=123.100\)
\(=12300\)
Hà Anh Hermione nhớ k
123*(154-24-30)=123*100=12300
không tin tính lai mà xem
Bai 12 tính nhanh
A = 123 ( 123 + 154 ) + 77²
B = 324 -(274+1)(96-1)
C=852+752+652+55²-45²-35²-25²-15²
a) \(A=123\left(123+154\right)+77^2\)
\(A=123^2+\left(123.154\right)+77^2=\left(123+77\right)^2=200^2=400\)
b) \(B=3^{24}-\left(2^{47}+1\right)\left(9^6-1\right)\)
\(B=3^{24}-\left(3^{12}-1\right)\left(3^{12}+1\right)\)
\(B=3^{24}-3^{24}+1=1\)
c) \(C=85^2+75^2+65^2+55^2-45^2-35^2-25^2-15^2\)
\(C=\left(85^2-15^2\right)+\left(75^2-25^2\right)+\left(65^2-35^2\right)+\left(55^2-45^2\right)\)
\(C=\left(85+15\right)\left(85-15\right)+\left(75+25\right)\left(75-25\right)+\left(65+35\right)\left(65-35\right)\left(55+45\right)\left(55-45\right)\)
\(C=100\left(60+50+40+30+20+10\right)\)
\(C=100.210=21000\)
Tính bằng cách thuận tiện nhât:
123 x 45 + 123 x 55
56 x 4 + 56 x3 + 56 x 2 + 56
[123 x 154 - 65 x 123] : 89
123×45+123×55
=123×(45+55)
=123×100
=12300
56×4+56×3+56×2+56
=56×4+56×3+56×2+56×1
=56×(4+3+2+1)
=56×10
=560
[ 123×154-65×123]:89
=[123×(154-65)]:89
= 123×89:89
=123×(89:89)
=123×1
=123
123 x 45 + 123 x 55
= 123 x ( 45 + 55 )
= 123 x 100
= 12300
56 x 4 + 56 x 3 + 56 x 2 + 56
= 56 x ( 4 + 3 + 2 + 1 )
= 56 x 10
= 560
[ 123 x 154 - 65 x 123 ] : 89
= [ 123 x ( 154 - 65 ) ] : 89
= [ 123 x 89 ] : 89
= 123
Học tốt #
123 x 45 + 123 x 55
= 123 x ( 45 + 55 )
= 123 x 100
= 12300
56 x 4 + 56 x 3 + 56 x 2 + 56
= 56 x ( 4 + 3 + 2 + 1 )
= 56 x 10
= 560
[123 x 154 - 65 x 123] : 89
= [ 123 x ( 154 - 65 ) ] : 89
= [ 123 x 89 ] : 89
= 123 x 89 : 89
= 123
Tính nhanh:
a) -37 +54 +(- 70)+(- 163)+246
b)-359 +181+(-123)+350+(-172)
c)-69 +53 + 46 +(- 94)+(- 14) + 78
d)13 -12 +11 +10 -9 + 8 -7 -6 +5 - 4 +3 +2 -1
a: =17-70-163+246
=-43-163+246
=246-206
=40
Bài 2. Tính hợp lý:
d) (-15) - 23+ (-85) -77;
e) (123 - 37) - 123; f) (-224) - (34 - 224);
g) 126 - (126- 33) h) (-53 - 23) - (567 - 53).
Em zai tui
d) ( - 15 ) - 23 + ( - 85 ) - 77
= ( - 15 - 85 ) - ( 23 + 77 )
= - 100 - 100
= - 200
e) ( 123 - 37 ) - 123
= ( 123 - 123 ) - 37
= 0 - 37
= - 37
f) ( - 224 ) - ( 34 - 224 )
= ( - 224 + 224 ) - 34
= 0 - 34
= - 34
g) 126 - ( 126 - 33 )
= ( 126 - 126 ) - 33
= 0 - 33
= - 33
h) ( - 53 - 23 ) - ( 567 - 53 )
= ( - 53 + 53 ) + ( - 23 - 567 )
= 0 - 590
= - 590
d) ( - 15 ) - 23 + ( - 85 ) - 77
= ( - 15 - 85 ) - ( 23 + 77 )
= - 100 - 100
= - 200
e) ( 123 - 37 ) - 123
= ( 123 - 123 ) - 37
= 0 - 37
= - 37
f) ( - 224 ) - ( 34 - 224 )
= ( - 224 + 224 ) - 34
= 0 - 34
= - 34
g) 126 - ( 126 - 33 )
= ( 126 - 126 ) - 33
= 0 - 33
= - 33
h) ( - 53 - 23 ) - ( 567 - 53 )
= ( - 53 + 53 ) + ( - 23 - 567 )
= 0 - 590
= - 590
Tính nhanh gia tri bt
a) 123(123+154) + 772
b) 324 - (274 +1)(96-1)
c) 12-22+32-42+52-62+....+20112-20122
123*77+123*23
`123xx77+123xx23`
`=123xx(77+23)`
`=123xx100`
`=12300`