A point starts from the origin of the number axis, first moves 3 units to the right, and then moves 7 units to the left, what is the number corresponding to the point at this time?
一个点从数轴原点开始，先向右移动3个单位，再向左移动7个单位的长度，这时点所对应的数为多少．
<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<result>4</result>