In a subtraction formula, the sum of the minuend, the subtrahend and the difference is 280, and the ratio of the subtrahend to the difference is 5:2. What is the subtrahend?
在一道减法算式中，被减数、减数、差的和是280，减数与差的比是5：2，求减数是多少？
<gadget id="calculator">280 / 2</gadget>
<output>140</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">140 * (5/7)</gadget>
<output>100</output>

<result>100</result>