When adding two numbers, one addend is decreased by 0.4, the other is increased by 2.6, and by how much
两个数相加，一个加数减少0.4，另一个数增加2.6，和增加多少
<gadget id="calculator">2.6 - 0.4</gadget>
<output>2.2</output>

<result>2.2</result>