A number (1/3) plus 2.8 is equal to 12.8. Find this number. (solution by equation)
一个数的(1/3)加上2.8，等于12.8，求这个数．(用方程解)
<gadget id="calculator">12.8 - 2.8</gadget>
<output>10</output>

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

<gadget id="calculator">10 / (1/3)</gadget>
<output>30</output>

<result>30</result>