In a subtraction, if the minuend is increased by 70 and the difference is decreased by 20, how much is the subtrahend increased.
在一个减法算式中，如果被减数增加70，差减少20，那么减数增加多少．
<gadget id="calculator">70 + 20</gadget>
<output>90</output>

<result>90</result>