The number of A is 3.5 less than the number of B, the number of A is 2.8, what is the number of B?
甲数比乙数少3.5，甲数是2.8，乙数是多少？
<gadget id="calculator">2.8 + 3.5</gadget>
<output>6.3</output>

<result>6.3</result>