12 cars form a convoy to move forward. Counting from front to back, the red car is the eighth. Then, counting from the back to the front, how many cars is it.
12辆汽车组成一列车队向前进．从前往后数，红色的汽车是第8辆．那么，从后往前数，它是第多少辆．
<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>