A psychiatrist has 4 patients that need 25 sessions in total. One of the patients needs 6 sessions. Another patient needs 5 more than that. How many sessions would the remaining patients need?
The second patient needs 6+5 = 
<gadget id="calculator">6+5</gadget>
<output>11</output>
11 sessions.
The first two patients need 6+11=
<gadget id="calculator">6+11</gadget>
<output>17</output>
17 sessions total.
25-17=
<gadget id="calculator">25-17</gadget>
<output>8</output>
8 sessions.

<result>8</result>