When Xiaoqiang was doing a subtraction problem, he mistakenly copied the subtrahend 680 into 860, and the difference was 270. What should be the correct difference?
小强在做一道减法题时，把被减数680错抄成了860，得到的差是270．正确的差应该是多少？
<gadget id="calculator">860 - 680</gadget>
<output>180</output>

<gadget id="calculator">270 - 180</gadget>
<output>90</output>

<result>90</result>