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

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

c) 

400 ml + 300 ml = 700 ml

800 ml : 4 = 200 ml

700 ml – 300 ml = 400 ml

200 ml x 4 = 800ml

x + 300 = 500 - 200

x + 300 = 300

          x = 300 - 300

          x = 100

ai k mik mik k lại 

x + 300 = 500 - 200

x + 300 = 300

x = 300 - 300

x = 0 

x-200=500+300

x-200=800

x      =800+200

x      =1000

K mk nha 

Mk sẽ k lại

x - 200 = 800

       x  =  800+200

       x  = 1000

x = 400 nha

ai tk mình mình tk lại cho

300 + x = 500 + 200

300 + x = 700

         x = 700 - 300

         x = 400

 x + 500 = 300 + 200

x + 500 = 500

x          = 500 - 500

x          = 0

x+500=300+200

x+500=500

x       =500-500

x       =0

x-200=500+300

x-200=800

x      =800+200

x      =1000

K mk nha 

Mk sẽ k lại

x + 200 = 800

x           = 800 - 200

x           = 600

9000

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