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

(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*100-137*100

23700-13700

10000

\(237.\left(42+58\right)-137.\left(58+42\right)\)

\(=237.100-137.100\)

\(=100.\left(237-137\right)\)

\(=100.100=10000\)

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

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

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

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

\(2019\times58+2019\times42+78\)

\(=2019\times\left(58+42\right)+78\)

\(=2019\times100+78\)

\(=201900+78\)

\(=201978\)

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

\(\left(100+58\right)\times58+\left(200-42\right)\times12\)

\(=158\times58+158\times12\)

\(=158\times\left(58+12\right)\)

\(=158\times70=11060\)

\(128\times72+14\times256\)

\(=128\times72+14\times2\times128\)

\(=128\times\left(72+28\right)\)

\(=128\times100=12800\)

\(157\times99+123+34\)

\(=157\times99+157\times1\)

\(=157\times\left(99+1\right)\)

\(=157\times100=15700\)

\(67+98\times45+23\)

\(=98\times45+90\)

\(=98\times45+45\times2\)

\(=45\times\left(98+2\right)\)

\(=45\times100=4500\)