(x-3.5)/3=28．
(x-3.5)/3=28．
<gadget id="calculator">3.5 / 3</gadget>
<output>1.166667</output>

<gadget id="calculator">1.166667 + 28</gadget>
<output>29.166667</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">29.166667 / (1/3)</gadget>
<output>87.500001</output>

<result>87.500001</result>