500 + x = 100 + 500

500 + x = 600

          x = 600 - 500

          x = 1001

300 - x = 300 + 200

300 - x = 500

         x = 300 - 500

         x = -200

400 - x = 200 + 400

400 - x = 600

         x = 400 - 600

         x = -200

k mk nha mk k l

ại ^_^

500 + 100 = 100 + 500

300 + 200 =  300 + 200

400 + 200  = 200 + 400

x + 400 = 500 + 100

x + 400 = 600

x          = 600 - 400 

x          = 200

x + 400 = 500 + 100

x + 400 = 600

          x = 600 - 400

          x = 200

ai k mk mk k lại ^_^

x + 400 = 500 - 100

x + 400 = 400

x =400 - 400

x = 0

Vậy x = 0

x + 400 = 500 - 100

x + 400 = 400

x = 400 - 400

x = 0

750

tk mình nha

x + 50 + 100 = 500 + 400

x + 50 + 100 = 900

x = 900 - 100 - 50

x = 750

k mk mk k lại

x + 100 =500

          x = 500 - 100

          x = 400

200 + x = 400

          x = 400 - 200

          x = 200

ai k mk mk k lại ^_^

x+100=500

       x=500-100

       x=400

200+x=400

       x=400-200

       x=200

a)x+400=500-100

 x+400=400

 x=400-400

 x=0

b)x+10=50

  x=50-10

  x=40

x + 400 = 500 - 100

x + 400 = 400

          x = 400 - 400

          x = 0

x + 10 = 50

        x = 50 -10

        x = 40

9000

100+100+200+200+300+300+400+400+500+500+600+600+700+700+800 = 6400

b) 200 x 4 = .800.....              300 x 2 = ..600....

200 x 2 = .400.....             300 x 3 = ...900...

400 x 2 = ...800...             500 x 1 = ..500....

100 x 4 = ..400....             100 x 3 = .300.....

800

400

800

400

600

900

500

300

100x200+200x500+200x400

=20000+100000+80000

=120000+80000

=200000

100 x 200 + 200 x 500 + 200 x 400

= 200 x ( 100 + 500 + 400 )

= 200 x 1000

= 200000