In a subtraction formula, the subtrahend remains unchanged and the subtrahend decreases by 4.5. If the original difference is 8, what is the time difference?
一道减法算式中，被减数不变，减数减小4.5，如果原来差是8，这时差是多少．
<gadget id="calculator">8 + 4.5</gadget>
<output>12.5</output>

<result>12.5</result>