19.2 is 42 less than 4.5 times of a certain number, find this number. (Solution of column equation)
19.2比某数的4.5倍少42，求这个数．(列方程解)
<gadget id="calculator">42 + 19.2</gadget>
<output>61.2</output>

<gadget id="calculator">61.2 / 4.5</gadget>
<output>13.6</output>

<result>13.6</result>