\(a,1999-2000+1=\left(1999+1\right)-2000=2000-2000=0\\ b,450:5+550:5=\left(450+550\right):5=1000:5=200\\ c,188\times7+188\times4-188=188\times\left(7+4-1\right)=188\times10=1880\)

a,1999−2000+1=(1999+1)−2000=2000−2000=0b,450:5+550:5=(450+550):5=1000:5=200c,188×7+188×4−188=188×(7+4−1)=188×10=1880

a) 1999 - 2000 + 1

= ( 1999 + 1 ) - 2000

= 2000 - 2000

= 0

b) 450 : 5 + 550 : 5

= ( 450 + 550 ) : 5 

= 1000 : 5

= 200

c) 188 x 7 + 188 x 4 - 188

= ( 7 + 4 - 1 ) x 188

= 10 x 188

= 1880

(450:50) x27=9x27=243

chúc bn hok tốt

(450:50)x27=9x27=243

Chúc bạn làm bài tốt.

450x0,45 + 1,5x30x3 + 5x9x2,5

= 450x0,45 + 4,5x30 + 45x2,5

= 450x0,45 + 0,45x300 + 0,45x250

= 0,45x(450 + 300 + 250) = 0,45x1000 = 450

(450 x 27) : 50

=(450:50)x27

=9x27

=243

\(\left(450\times27\right):50=\left(450:50\right)\times27=9\times27=243\)

\(\text{( 450 x 27 ) : 50}\)

\(=\text{(450:50) x27}\)

\(\text{=9x27}\)

\(\text{=243}\)

(25x36):9+450-75-25

= 900 : 9 + 450 - 75 -25

= 100 + ( 450 - 75-25)

= 100 + 350

= 450

450

=450

Bài giải

(450 x 480 x 44) : (15 x 12 x 11)

(450 : 15 = 30; 480 : 12 = 40; 44 : 11 = 4 Suy ra)

= 30 x 40 x 4

= 1200 x 4

= 4800

Cảm ơn bạn Trần Thị Mạnh đã giúp Ting giải bài toán này nhé! 

You're welcome

a: =150x70=10500

b: =999(15+85)=99900

c: =72072:72=1001

a.31500:3=10500

b.(165:11+85)x999

=(15+85)x999

=100x999

=99900

c.(72072:6):12

=12012:12

=1001

d.18180:36=505

a.31500:3=10500

b.(165:11+85)x999

=(15+85)x999

=100x999

=99900

c.(72072:6):12

=12012:12

=1001

d.18180:36=505

(450\(\times\)27):50

=12150:50

=243

(450 x 27) : 50

= (450 : 50) x 27

= 9 x 27

= 243

(45027):50

=(450:5)\(\times\)27

=90\(\times\)27

=2430

(5 x 5 x 36):9 + 450 - 100

=100+350=450