2 times a number plus the product of 3 and 1.5, the sum is 7, find this number. (Solution of column equation)
一个数的2倍加上3与1.5的积，和是7，求这个数．(列方程解)
<gadget id="calculator">3 * 1.5</gadget>
<output>4.5</output>

<gadget id="calculator">7 - 4.5</gadget>
<output>2.5</output>

<gadget id="calculator">2.5 / 2</gadget>
<output>1.25</output>

<result>1.25</result>