x : 5 =1400-900
x-30=1000-200
Х:5=1400-900 х:5=500 х=500*5 х=2500 ____________ 2500:5=500 500=500 x-30=1000-200 х-30=800 х=800+30 х=830 ____________ 830-30=800 800=800