6 2.5 minus 7 times a number, the difference is 4.5, what is this number?
6个2.5减去一个数的7倍，差是4.5，这个数是多少？
<gadget id="calculator">2.5 * 6</gadget>
<output>15</output>

<gadget id="calculator">15 - 4.5</gadget>
<output>10.5</output>

<gadget id="calculator">10.5 / 7</gadget>
<output>1.5</output>

<result>1.5</result>