John attends a protest for 4 days.  He then attends a second protest for 25% longer than the first.  How many days did he spend protesting?
The second protest was 4*.25=
<gadget id="calculator">4*.25</gadget>
<output>1</output>
1 day longer than the first.
So the second protest was 4+1=
<gadget id="calculator">4+1</gadget>
<output>5</output>
5 days.
Thus he spent 4+5=
<gadget id="calculator">4+5</gadget>
<output>9</output>
9 days protesting.

<result>9</result>