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.

34226 OK

34226 nha

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

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) \(C=85^2+75^2+65^2+55^2-45^2-35^2-25^2-15^2\)

\(C=\left(85^2-15^2\right)+\left(75^2-25^2\right)+\left(65^2-35^2\right)+\left(55^2-45^2\right)\)

\(C=\left(85+15\right)\left(85-15\right)+\left(75+25\right)\left(75-25\right)+\left(65+35\right)\left(65-35\right)\left(55+45\right)\left(55-45\right)\)

\(C=100\left(60+50+40+30+20+10\right)\)

\(C=100.210=21000\)

A=40000

B=1

C=16000

123 + 698 + 77 + 2

= ( 123 + 77 ) + ( 698 + 2 )

= 200 + 700

= 900

#Hok_tốt

( 123 + 77 ) + ( 698 + 2 )

200 + 700

900

123+698+77+2

=(123+77)+(698+2)

=200+700=900

Chọn A

− 123 + 77 + − 257 + 23 − 43 = − 123 + 23 + − 257 − 43 + 77 = − 100 + − 300 + 77 = − 400 + 77 = − 323

a) =38 dùng mt

b) -114

Ai tích mk mk sẽ tích lại

nhưng mà mình cần cách giải cơ bạn ạk

1. 1996 ++ 3012 + 5988 + 7004

= ( 1996 + 7004 ) + ( 3012 + 5988)

= 9000 + 9000

= 18000

2.1253 + 254 + 2345 - 253 - 154

= ( 1253 - 253 ) + ( 254 - 154 )

= 1000 + 100

= 1100

3. 123 + 456 + 77 + 546

= ( 123 + 77 ) + ( 456 + 546)

= 200 + 1002

= 1202

4.50 - 5 - 5 - 5 - 5 - 5 - 5 - 5 - 5 - 5 - 5 - 5

= 50 - ( 5 x 11 )

= 50 - 55

= -5

5.143 - ( 80 + 43 )

= 143 - 123

= 20

Chúc bạn học tốt!

1.1996+7004=9000+3012+5988=1800