\(815-23-77+185\)

\(=\left(815+185\right)-\left(23+77\right)\)

\(=1000-100=900\)

815-23-77+185

= 792-77+185

=715+185

=900

\(815-23-77+185\)

\(=(815+185)-\left(23+77\right)\)

\(=1000-100\)

\(=900\)

815  - 23 -77 +185

= ( 815 + 185 ) - ( 23 + 77 )

= 1 000 - 100

= 900

Tính bằng cách thuận tiện nhất

\(815-23-77+185\)

\(=\left(815+185\right)\)\(-\)\(\left(23+87\right)\)

\(=1000-100\)

\(=900\)

Hok tốt

815 - 23 - 77 + 185

= (815 + 185) - ( 23 + 77)

= 1000 - 100

= 900

Theo đề bài : 815 - 23 - 27 + 185 theo cách thuận tiện như sau :

= ( 815 + 185 ) - ( 23 + 77 )

=      1000       -       100

=              900

815-23-77+185 = (815+185)-(23+77) = 1000- 100 = 900

a) 815 – 23 – 77 +185 = (815 + 185) – (23+77) = 1000 – 100 = 900

b) 3145 – 246 + 2347 – 145 + 4246 – 347

= (3145-145) + (4246 – 246) + (2347 – 347)

= 3000 + 4000 + 2000 = 9000

c) (2018:1 – 2018.1):(2018.2008+2018.2002) = 0 : (2018.2008+2018.2002) = 0

d) (9 – 8 – 7 – 6 – … – 2 – 1).(500.9 – 250.18)

= (9 – 8 – 7 – 6 – … – 2 – 1).(500.9 – 250.2.9)

= (9 – 8 – 7 – 6 – … – 2 – 1).(500.9 – 500.9)

= (9 – 8 – 7 – 6 – … – 2 – 1).0 = 0

a,(815+185)-(23+77)

=1000-100=900

b,(2496+7504)+(5347+4653)+3145

=10000+               10000          +3145

=23146

c,(1+19)+(3+17)+(5+15)+(7+13)+(9+11)

=20+20+20+20+20=100

d,(52+28)+(37+63)-(42+38)

=80+100-80=100

mk nha

a,(815+185)-(23+77)

=1000-100=900

b,(2496+7504)+(5347+4653)+3145

=10000+               10000          +3145

=23146

c,(1+19)+(3+17)+(5+15)+(7+13)+(9+11)

=20+20+20+20+20=100

d,(52+28)+(37+63)-(42+38)

=80+100-80=100

mk nha

Tính nhanh:

a. 815 - 23 - 77 + 185

= (815+185)-(23+77)

=1000 - 100

= 900

b. 3145 + 2496 + 5347 + 7504 + 4653

=3145+(2496+7504)+(5347+4653)

= 3145+10 000 + 10 000

= 3145 + 20 000

= 23 145

c. 1 + 3 + 5 + 7 + 9+ 11 + 13 + 15 + 17 + 19

=(1+19)+(3+17)+(5+15)+(7+13)+(9+11)

= 20  +   20    +   20 + 20 + 20

= 20 × 5 

= 100

d. 52 - 42 + 37 + 28 - 38 + 63

= ( 52 + 28 ) - ( 42 + 38 ) + ( 37 + 63 )

=  80  -  80  + 100

= 0 + 100

= 100 

815 - 23 - 77 + 85 

= 815 + 85 - 23 - 77

= ( 815 + 85 ) - ( 23 + 77 )

= 900 - 100

= 800

\(815-23-77+85\)

\(=\left(815+85\right)-\left(23+77\right)\)

\(=900-100=800\)

= 800

HOK TỐT

c ) 815 - 23 - 77 + 185 

= ( 815 + 185 ) - ( 23 + 77 )

= 1000 - 100 = 900

m ) 8 x 427 x 3 + 6 x 573 x 4

= 24 x 427 + 24 x 573

= 24 x ( 427 + 573 ) 

= 24 x 1000

= 24000

g ) 52 - 42 + 37 + 28 - 38 + 63

= ( 52 + 28 ) - ( 42 + 38 ) + ( 37 + 63 )

= 80 - 80 + 100

= 0 + 100

= 100

h ) 35 x 18 - 9 x 70 + 100

= 7 x 5 x 9 x 2 - 9 x 7 x 5 x 2 + 100

= 0 + 100

= 100

n ) 2008 x 867 + 2009 x 133

= 2008 x 867 + ( 2008 + 1 ) x 133

= 2008 x 867 + 2008 x 133 + 133

= 2008 x ( 867 + 133 ) + 133

= 2008 x 1000 + 133

= 2008000 + 133

= 2008133

i ) 326 x 78 + 327 x 22

= 326 x 78 + ( 326 + 1 ) x 22

= 326 x 78 + 326 x 22 + 22

= 326 x ( 78 + 22 )  + 22

= 326 x 100 + 22

= 32600 +22

= 32622

q ) ( 20 + 21 + 22 + 23 + 24 + 25 ) x ( 16 - 2 x 8 ) 

= ( 20 + 21 + 22 + 23 + 24 + 25 ) x ( 16 - 16) 

= ( 20 + 21 + 22 + 23 + 24 + 25 ) x 0

= 0

thank bạn

a, 100   b, 45   c, -20   d, 46.

a,100

b,45

c,-20

d,46

a, 100   b, 45   c, -20   d, 46