The sum of the minuend plus the subtrahend plus the difference is 480. If the difference is 3 times the subtrahend, what is the subtrahend?
被减数加上减数加上差和是480，若差是减数的3倍，减数是多少．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">480 / 2 / 4</gadget>
<output>60</output>

<result>60</result>