When multiplying two numbers, if one factor increases by 4 and the other factor remains unchanged, then the product increases by 28; if one factor remains unchanged and the other factor decreases by 6, then the product decreases by 120, what is the original product?
两个数相乘，如果一个因数增加4，另一个因数不变，那么积增加28；如果一个因数不变，另一个因数减少6，那么积减少120，原来的积是多少？
<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<gadget id="calculator">120 / 6</gadget>
<output>20</output>

<gadget id="calculator">7 * 20</gadget>
<output>140</output>

<result>140</result>