The sum of the three numbers A, B, and C is 360. The number A is 20 less than the number B, and the number C is 20 more than the number B. What is the number A?
甲、乙、丙三个数的和是360，甲数比乙数少20，丙数比乙数多20，甲数是多少．
<gadget id="calculator">360 - 20</gadget>
<output>340</output>

<gadget id="calculator">20 + 340</gadget>
<output>360</output>

<gadget id="calculator">1 + 1 + 1</gadget>
<output>3</output>

<gadget id="calculator">360 / 3</gadget>
<output>120</output>

<gadget id="calculator">120 - 20</gadget>
<output>100</output>

<result>100</result>