Tính nhanh
42.(58-11)-58.(11+42)
Tính nhanh:
58*42+32*58+74*42=?
58x42+32x58+74x42
= 58x ( 42+ 32 ) + 74 x 42
=58 x 74 + 74 x 42
= 74 x ( 58+ 42)
=74 x 100
=7 400
58.(42+32)+74.42=58.74+74.42=74.(58+42)=74.100=7400
Tính nhanh : ( 100 + 42 ) x 42 + ( 200 - 58 ) x 58
(100+42) x42+(200-58)x58
=142x42+142x58
=142x(42+58)
=142x100
=14200
\(\left(100+42\right)\times42+\left(200-58\right)\times58\)
\(=142\times42+142\times58\)
\(=142\times\left(42+58\right)\)
\(=142\times100=14200\)
142 x 42 + 142 x 58
= 142 x (42 +58)
=142 X 100
=14200
K NHÉ +kb
237*(42+58)-137*(58+42) tính nhanh nha mọi người cần gấp
Tính nhanh
a,1,75:0,25+1,75:0,5+1,75:0,25
b,26,3×101-26-0,3
c,(200-58)×42+(100+42)×58
a) 1,75 : 0,25 + 1,75 : 0,5 + 1,75 : 0,25
= 1, 75 : \(\dfrac{1}{4}\) + 1,75 : \(\dfrac{1}{2}\) + 1,75 : \(\dfrac{1}{4}\)
= 1,75 x 4 + 1,75 x 2 + 1,75 x 4
= 1,75 x (4 + 2 + 4)
= 1,75 x 10
= 17,5
b) 26,3 x 101 - 26 - 0,3
= 26,3 x 101 - (26 + 0,3)
= 26,3 x 101 - 26,3 x 1
= 26,3 x (101 - 1)
= 26,3 x 100
= 2630
c) (200 - 58) x 42 + (100 + 42) x 58
= 142 x 42 + 142 x 58
= 142 x (42 + 58)
= 142 x 100
= 14200
Tính nhanh :
12.7 + 12.7 + 12.7 + 12.7 x 8 - 12.7
( 100 + 42 ) x 42 + ( 200 - 58 ) x 58
12,7 + 12,7 + 12,7 + 12,7 x 8 - 12,7
= 12,7 x (1 + 1 + 1 + 8 - 1)
= 12,7 x 10
= 127
(100 + 42) x 42 + (200 - 58) x 58
= 142 x 42 + 142 x 58
= 142 x (42 x 58)
= 142 x 100
= 14200
a.
12,7 + 12,7 + 12,7 + 12,7 x 8 - 12,7
= 12,7 x ( 1 + 1 + 1 + 8 - 1 )
= 12,7 x 10
= 127
b.
( 100 + 42 ) x 42 + ( 200 - 58 ) x 58
= 142 x 42 + 142 x 58
= 142 x ( 42 + 58 )
= 142 x 100
= 14200
Tính bằng cách thuận tiện :
A) 38+42+46+50+54+58+62
B) 11+137+72+63+128+89
a) \(38+42+46+50+54+58+62\)
\(=\left(38+62\right)+\left(42+58\right)+\left(46+54\right)+50\)
\(=100+100+100+50\)
\(=100\cdot3+50\)
\(=350\)
b) \(11+137+72+63+128+89\)
\(=\left(11+89\right)+\left(137+63\right)+\left(72+128\right)\)
\(=100+200+200\)
\(=300+200\)
\(=500\)
A) = (38 + 62) + (42 + 58) + (46 + 54) + 50
= 100 + 100 + 100 + 50
= 350
B) = (11 + 89) + (137 + 63) + (72 + 128)
= 100 + 200 + 200
= 500
A) (38 + 62) + ( 42 + 58 ) + ( 46 + 54 ) + 50
= 100 + 100+ 100 + 50
= 350
B) ( 11 + 89 ) + ( 137 + 63 ) + ( 72 + 128 )
= 100 + 200 + 200
= 500
k mk nha mk đầu tiên đó
1.tính nhanh a,(4+4)×(2019+2019+...+2019) "Có 125 số 2019"
b,(42+42+...+42)+(125+125+...+125)
"Có 125 số 42 ;có 58 số 125"
a) (4+4)x(2019 +2019 +.....+2019)
= 8 x 125 x 2019
= (8 x 125) x 2019
= 1000 x 2019
= 2019000
b) ( 42+42+...+42)+(125+125+....+125)
= 42 x 125 + 58 x 125
= 125 x ( 42 + 58)
= 125 x 100
= 12500
42+42+...+42)+(125+125+....+125)
= 42 x 125 + 58 x 125
= 125 x ( 42 + 58)
= 125 x 100
= 12500
Tính nhanh
2019 x 58 + 2019 x 42 + 78
\(2019\times58+2019\times42+78\)
\(=2019\times\left(58+42\right)+78\)
\(=2019\times100+78\)
\(=201900+78\)
\(=201978\)
2019 x 58 + 2019 x 42 + 78
= 2019 x ( 58 + 42 ) + 78
= 2019 x 100 + 78
= 201900 + 78 = 201978
A = 2019 x 58 + 2019 x 42 + 78
A = (2019 x 58 + 2019 x 42) + 78
A = 2019 x ( 58 + 42) + 78
A = 2019 x 100 + 78
A = 201900 + 78
A = 201978
tính nhanh
( 100 + 58 ) x 58 + ( 200 - 42 ) x 12
128 x72 + 14 x 256
157 x99 + 123 + 34
67 + 98 x 45 + 23
\(\left(100+58\right)\times58+\left(200-42\right)\times12\)
\(=158\times58+158\times12\)
\(=158\times\left(58+12\right)\)
\(=158\times70=11060\)
\(128\times72+14\times256\)
\(=128\times72+14\times2\times128\)
\(=128\times\left(72+28\right)\)
\(=128\times100=12800\)
\(157\times99+123+34\)
\(=157\times99+157\times1\)
\(=157\times\left(99+1\right)\)
\(=157\times100=15700\)
\(67+98\times45+23\)
\(=98\times45+90\)
\(=98\times45+45\times2\)
\(=45\times\left(98+2\right)\)
\(=45\times100=4500\)