A's number is 43.2, which is 8.7 more than B's number. What is B's number? (use x to represent the unknown)
甲数是43.2，比乙数多8.7，乙数是多少？(用x表示未知数)
<gadget id="calculator">43.2 - 8.7</gadget>
<output>34.5</output>

<result>34.5</result>