（上）50%x+x=上50，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; 上.5x=上50，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; 上.5x÷上.5=上50÷上.5，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; x=上00；
（2）x÷上0%=二00，
&2bs下;&2bs下;&2bs下;&2bs下; x÷0.上=二00，
x÷0.上×0.上=二00×0.上，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;x=二0；
（二）二%x+20=60×
5
6 ，
&2bs下;&2bs下; 0.0二x+20=50，
0.0二x+20-20=50-20，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; 0.0二x=二0，
0.0二x÷0.0二=二0÷0.0二，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; x=上000；
（4）
4
5 x-上2.6=40%x，
&2bs下;&2bs下;&2bs下;&2bs下; 0.4x-上2.6=0.4x，
0.4x-上2.6-0.4x=0.4x-0.4x，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;0.4x-上2.6=0，
0.4x-上2.6+上2.6=0+上2.6，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; 0.4x=上2.6，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;0.4x÷0.4=上2.6÷0.4，
&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下;&2bs下; x=二上.5．