16+17+18+19+20+21+22

=120

K minh nha

\(300+500+800\)

\(=800+800\)

\(=800\times2\)

\(=1600\)

300+500+800=1600

x + 70 = 100

x = 100 - 70

x = 30

K mk nha

Mk k lại

x + 70 = 100

x        = 100 - 70

x        = 30

Vậy x = 30

ai k mik mik k lại

X+10=20X5

X+10=100

X=100-10

X=90

x + 10 = 100

=>x     = 100 - 10

=>x     =       90

k nhé

100+200+500

=300+500

=800

100 + 200 + 500 = 800

x + 100 = 500 + 200

x + 100 = 700

         x  = 700 - 100

         x  = 600

tk mk mk tk lại

x + 100 = 500 + 200

x + 100 = 700 

x          = 700 - 100

x          = 600

x + 300 = 900 - 400 

x + 300 =   500

x          = 500 - 300

x          =       200

ai tk mk mk tk lại ^_^

x + 300 = 900 - 400

x + 300 = 500

          x = 500 - 300

          x = 200

ai k mk mk k l

ại ^_^

x + 100 = 300 + 200

x + 100 = 500

          x = 500 - 100

          x = 400

ai k mk mk k l

ại ^_^

x + 100 = 300 + 200 

x + 100 = 500

x          = 500 - 100

x          =   400

ai tk mk mk tk lại 

300 + 400 + 700

= 700 + 700

= 1400

300 + 400 + 700

= (300 + 700) + 400

= 1000 + 400

= 1400

\(x+300=600-200\)

\(x+300=400\)

\(x=400-300\)

\(x=100\)

\(x+300=600-200\)

\(x+300=400\)

\(x=400-300\)

\(x=100\)

THỬ LẠI

\(100+300=600-200\)

\(400=400\)

x + 300 = 600 - 200

x + 300 = 400

x          = 400 - 300

x          = 100