<span>X+(619-392)=719+320</span>
<span>х+227=1039</span>
<span>х=1039-227</span>
<span>х=812</span>
<span>120+880-X=56*50</span>
<span>1000-х=2800</span>
<span>-х=2800-1000</span>
<span>-х=1800</span>
<span>х=1800:(-1)</span>
<span>х=-1800</span>
33,66,99
100,200,300,400,500,600,700,800,900