fix issues with exercises

Author: oscarlevin

generated-assets/rs/webwork/images/webwork-127-image-1.pdf

@@ -132,7 +132,7 @@
                   How many ways can we distribute the cookies if Albie <em>does not</em> get more than 3 cookies?
                 </p>
                 <p>
-                  <var name="Compute(C(12,2)-C(8,2))" width="5" />
+                  <var name="Compute(C(12,2) - C(8,2))" width="5" />
                 </p>
               </statement>
             </task>
@@ -162,7 +162,7 @@
                   Using the Principle of Inclusion/Exclusion for two sets, how many ways can we distribute the cookies if <em>at least one</em> of Albie or Bertie gets more than 3 cookies?  So either Albie gets more than 3 cookies, Bertie gets more than 3 cookies, or both get more than 3 cookies.
                 </p>
                 <p>
-                  <var name="Compute(C(8,2)+C(8,2)-C(4,2))" width="5" />
+                  <var name="Compute(C(8,2) + C(8,2) - C(4,2))" width="5" />
                 </p>
               </statement>
             </task>
@@ -172,7 +172,7 @@
                   How many ways can we distribute the cookies if <em>neither</em> Albie nor Bertie gets more than 3 cookies?
                 </p>
                 <p>
-                  <var name="Compute(C(12,2)-(C(8,2)+C(8,2)-C(4,2)))" width="5" />
+                  <var name="Compute(C(12,2) - (C(8,2) + C(8,2) - C(4,2)))" width="5" />
                 </p>
               </statement>
             </task>

generated-assets/rs/webwork/images/webwork-127-image-1.png

@@ -137,7 +137,7 @@ for i in range(4):
       <exercise label="pa-counting-probability-2">
         <webwork>
           <pg-code>
-            
+            Context("IntegerFunctions");
           </pg-code>
 
           <introduction>
@@ -246,7 +246,7 @@ for i in range(4):
                 Among the 30 people, either they all have different birthdays or at least two share a birthday.  Since this is certain, its probability is 1.  So what is the probability that at least two people (out of the 30) share a birthday? 
               </p>
               <p>
-                <var name="Compute(1-$prob)" width="10"/>
+                <var name="Compute(1 - $prob)" width="10"/>
               </p>
             </statement>
           </task>

generated-assets/rs/webwork/images/webwork-197-image-1.pdf

@@ -247,7 +247,7 @@
                 Guess a closed formula for the number of dots in the <m>n</m>th figure.
               </p>
               <p component="interactive">
-                <m>a_n = </m> <var name="Formula('2*n**4')" width="20" />.
+                <m>a_n = </m> <var name="Formula('2*3**n')" width="20" />.
               </p>
             </statement>
           </task>