\(\text{a.61 x 23 + 39 x 22}\)

\(=61.22+1+39.22\)

\(=22.\left(61+39\right)+1\)

\(=22.100+1\)

\(=2200+1\)

\(=2201\)

mình chỉ làm được 1 câu thôi

hok tốt

61*23+39*22

=(61+39)*22+61

=100*22+61

=2200+61

=2261

61 x 23 + 39 x 22 = 61 x ( 22 + 1 ) + 39 x 22 = 61 x 22 + 61 + 39 x 22 = 22 x ( 61 + 39 ) + 61 = 22 x 100 + 61 = 2 200 +61 = 2 261

23.49+77.177+23.61-77.67

=23.(49+61)+77.(177-67)

=23.110+77.110

=110.(23+77)

=110.100=11000

k nha

23 * 49 + 77*177 + 23*61 - 77* 67 = 23(49+ 61) + 77 (177 - 67) = 23* 110 + 77* 110 = (23+ 77) * 110 = 100 * 110 = 11 000

(23 + 77) + ( 56 + 144) + ( 79 + 21)

= 100 + 200 + 100

= 400. 

k cho mik nhé! Thanks

23 + 56 + 79 + 144 + 77 + 21

= ( 23 + 21 ) + ( 79 + 77 ) + ( 56 + 144 )

= 44 + 156 + 200

= 200 + 200

= 400

oc cho

( -2007 ) - ( 12 - 2007 )

= -2007 - 12 + 2007

= ( -2007 + 2007 ) -12

= 0 -12

= -12

( 28 + 39 ) + ( 168 - 28 - 39 )

= 28 + 39 + 168 - 28 - 39

= ( 28 - 28 ) + ( 39 - 39 ) + 168

= 0 + 0 + 168

= 168

( 23 - 145 + 59 ) - ( 23 + 59 )

= 23 - 145 + 59 - 23 - 59

= ( 23 - 23 ) + ( 59 - 59 ) -145

= 0 + 0 - 145

= -145

( -23 ) - ( 77 + 1000 )

= -23 - 77 + 1000

= ( -23 -77 ) + 1000

= -1000 + 1000

= 0

( 427 - 2019 ) - ( 27 - 2019 )

= 427 - 2019 - 27 + 2019

= ( 427 - 27 ) - ( 2019 - 2019 )

= 400 - 0

= 400

Bạn k cho mk nha !!!

-2017

-26914

480

-450

1) - 135 - 2017 + 9 x 15

= - 135 - 2017 + 135

= ( - 135 + 135 ) - 2017

= 0 - 2017

= - 2017

2) - 39 x ( 250 - 87 ) - 61 x ( 240 + 97 )

= - 39 x 163 - 61 x 337

= - 6357 - 20557

= - 26914

3) 65 + 135 - 35 + 9 x 35

= 65 + 135 - 35 + 315

= ( 65 + 315 ) + ( 135 - 35 )

= 380 + 100

= 480

4) - 15 x ( 23 + 157 ) + 15 x 157 - 15 x 7

= 15 x ( - 180 ) + 15 x 157 - 15 x 7 

= 15 x ( - 180 + 157 - 7 )

= 15 x ( - 30 )

= - 450

77 : 2 = 38 ( dư 1 )

77 : 3 = 25 ( dư 2 )

77 : 4 = 19 ( dư 1 )

77 : 5 = 15 ( dư 2 )

77 : 2 = 38 ( dư 1 )

77 : 3 = 25 ( dư 2 )

77 : 4 = 19 ( dư 1 )

77 : 5 = 15 ( dư 2 )

_HT_

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854 + 23 + 77 + 146

= 877 + 77 + 146

= 954 + 146

= 1100

mk nhanh nhất nha bn

\(854+23+77+146\)

\(=\left(854+146\right)+\left(23+77\right)\)

\(=1000+100\)

\(=1100\)

854 + 23 + 77 + 146 = (854 + 146) + (23 + 77) = 1000 + 100 = 1100

27/23 + 5/21 - 4/23 + 6/21 + 1/2

=( 27/23 - 4/23 ) + ( 5/21 + 6/21 ) + 1/2

= 23/23 + 11/21 + 1/2

= 1 + 11/21 + 1/2

= 32/21 + 1/2 

= 85/42

\(\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+\frac{6}{21}+\frac{1}{2}\)

\(=(\frac{27}{23}-\frac{4}{23})+(\frac{5}{21}+\frac{6}{21})+\frac{1}{2}\)

\(=1+\frac{11}{21}+\frac{1}{2}\)

\(=\frac{32}{21}+\frac{1}{2}=\frac{85}{42}\)

Chúc bạn học tốt

\(\frac{27}{23}+\frac{5}{21}-\frac{4}{23}+\frac{6}{21}+\frac{1}{2}\)

\(=\left(\frac{27}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{6}{21}\right)+\frac{1}{2}\)

\(=\frac{23}{23}+\frac{11}{21}+\frac{1}{2}\)

\(=1+\frac{11}{21}+\frac{1}{2}\)

\(=\frac{21}{21}+\frac{11}{21}+\frac{1}{2}\)

\(=\frac{32}{21}+\frac{1}{2}=\frac{64}{42}+\frac{21}{42}=\frac{85}{42}\)