The sum of the three numbers A, B, and C is 11.25, the sum of the two numbers A and B is 7.18, and the sum of the two numbers A and C is 6.75, so what is the number A?
甲、乙、丙三个数的和是11.25，甲乙两个数的和是7.18，甲丙两个数的和是6.75，那么甲数是多少．
<gadget id="calculator">11.25 - 7.18</gadget>
<output>4.07</output>

<gadget id="calculator">6.75 - 4.07</gadget>
<output>2.68</output>

<result>2.68</result>