The sum of A, B, and C is 91. It is known that A is 17.5, B is 29.8, and what is C.
甲、乙、丙的和是91，已知甲是17.5，乙是29.8，丙是多少．
<gadget id="calculator">91 - 17.5 - 29.8</gadget>
<output>43.7</output>

<result>43.7</result>