1.5 times of a number is 12.6 less than its 4.5 times. Find this number?
一个数的1.5倍比它的4.5倍少12.6，求这个数？
<gadget id="calculator">4.5 - 1.5</gadget>
<output>3</output>

<gadget id="calculator">12.6 / 3</gadget>
<output>4.2</output>

<result>4.2</result>