On the number axis, starting from the point representing 0, move 3 unit lengths to the right to point A, and then move 6 unit lengths to the left from point A to point B, what is the number represented by point B?
在数轴上，从表示0的点出发，向右移动3个单位长度到A点，再从A点出发向左移动6个单位长度到B点，B点表示的数是多少．
<gadget id="calculator">0 + 3</gadget>
<output>3</output>

<result>3</result>