If the minuend increases by 3.6 and the subtrahend decreases by 2.9, how much does their difference increase?
如果被减数增加3.6，减数减少2.9，那么它们的差增加多少．
<gadget id="calculator">7 + 3.6</gadget>
<output>10.6</output>

<gadget id="calculator">5 - 2.9</gadget>
<output>2.1</output>

<gadget id="calculator">10.6 - 2.1</gadget>
<output>8.5</output>

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

<gadget id="calculator">8.5 - 2</gadget>
<output>6.5</output>

<result>6.5</result>