The sum of the numbers A and B is 12.3, and the number B is 1.23. What is the number A?
甲、乙两数的和是12.3，乙数是1.23，求甲数是多少？
<gadget id="calculator">12.3 - 1.23</gadget>
<output>11.07</output>

<result>11.07</result>