The average of the three numbers A, B and C is 86, where A is 90 and B is 83, what is C?
甲、乙、丙三个数的平均数是86，其中甲为90，乙为83，则丙为多少
<gadget id="calculator">86 * 3</gadget>
<output>258</output>

<gadget id="calculator">258 - 90 - 83</gadget>
<output>85</output>

<result>85</result>