diff --git a/doc/boostbook/numeric_concept.xml b/doc/boostbook/numeric_concept.xml
index 82c7753..42145bf 100644
--- a/doc/boostbook/numeric_concept.xml
+++ b/doc/boostbook/numeric_concept.xml
@@ -128,6 +128,12 @@
               <entry>true or false</entry>
             </row>
 
+            <row>
+              <entry><code>std::numeric_limits&lt;T&gt;::is_signed</code></entry>
+
+              <entry>true or false</entry>
+            </row>
+
             <row>
               <entry><code>os &lt;&lt; t</code></entry>
 
diff --git a/doc/boostbook/tutorial.xml b/doc/boostbook/tutorial.xml
index aaee84a..e704811 100644
--- a/doc/boostbook/tutorial.xml
+++ b/doc/boostbook/tutorial.xml
@@ -20,15 +20,11 @@
     responsibility to ensure such undefined behavior is avoided.</para>
 
     <para>This program demonstrates this problem. The solution is to replace
-    instances of <code>char</code> type with <code>safe&lt;char&gt;</code>
+    instances of <code>int</code> type with <code>safe&lt;int&gt;</code>
     type.</para>
 
     <programlisting><xi:include href="../../examples/example1.cpp"
         parse="text" xmlns:xi="http://www.w3.org/2001/XInclude"/></programlisting>
-
-    <para>Note that I've used <code>char</code> types in this example to make
-    the problem and solution easier to see. The exact same example could have
-    been done with <code>int</code> types albeit with different values.</para>
   </section>
 
   <section id="safe_numerics.tutorial.2">
diff --git a/examples/example10.cpp b/examples/example10.cpp
index ae4bf02..fc2e99b 100644
--- a/examples/example10.cpp
+++ b/examples/example10.cpp
@@ -17,7 +17,7 @@ void safe_f(
 }
 
 int main(){
-    cout << "example 10: ";
+    cout << "example 4: ";
     cout << "mixing types produces surprising results" << endl;
     try {
         std::cout << "Not using safe numerics" << std::endl;
diff --git a/examples/example4.cpp b/examples/example4.cpp
index 845e2dd..1ff4f22 100644
--- a/examples/example4.cpp
+++ b/examples/example4.cpp
@@ -4,7 +4,7 @@
 #include "../include/safe_integer.hpp"
 
 int main(){
-    std::cout << "example 4: ";
+    std::cout << "example 3: ";
     std::cout << "implicit conversions change data values" << std::endl;
     std::cout << "Not using safe numerics" << std::endl;
     
diff --git a/examples/example7.cpp b/examples/example7.cpp
index de5f8ca..9ce3b0f 100644
--- a/examples/example7.cpp
+++ b/examples/example7.cpp
@@ -23,7 +23,7 @@ unsigned int convert(
 }
 
 // Use safe numeric to enforce program contract automatically
-// define convient typenames for hours and minutes hh:mm
+// define convenient typenames for hours and minutes hh:mm
 using hours_t = boost::numeric::safe_unsigned_range<0, 23>;
 using minutes_t = boost::numeric::safe_unsigned_range<0, 59>;
 
@@ -36,7 +36,7 @@ auto safe_convert(const hours_t & hours, const minutes_t & minutes) {
 }
 
 int main(int argc, const char * argv[]){
-    std::cout << "example 7: ";
+    std::cout << "example 8: ";
     std::cout << "enforce contracts with zero runtime cost" << std::endl;
     std::cout << "Not using safe numerics" << std::endl;
 
@@ -52,10 +52,10 @@ int main(int argc, const char * argv[]){
     std::cout << "Using safe numerics" << std::endl;
 
     try {
-        // parameters are guarenteed to meet requirements
+        // parameters are guaranteed to meet requirements
         hours_t hours(10);
         minutes_t minutes(83);  // interrupt thrown here
-        // so the following will never throw
+        // so the following will never fail
         safe_convert(hours, minutes);
     }
     catch(std::exception e){
@@ -65,7 +65,7 @@ int main(int argc, const char * argv[]){
     }
 
     try {
-        // parameters are guarenteed to meet requirements when
+        // parameters are guaranteed to meet requirements when
         // constructed on the stack
         safe_convert(hours_t(10), minutes_t(83));
     }
@@ -76,7 +76,7 @@ int main(int argc, const char * argv[]){
     }
 
     try {
-        // parameters are guarenteed to meet requirements when
+        // parameters are guaranteed to meet requirements when
         // implicitly constructed to safe types to match function signature
         safe_convert(10, 83);
     }
@@ -102,7 +102,7 @@ int main(int argc, const char * argv[]){
         convert(hours, minutes); // zero (depending on compiler) runtime overhead
 
         // since unsafe types can be implicitly converted to corresponding
-        // safe types we can just pass the unsafe types.  checkin will occur
+        // safe types we can just pass the unsafe types.  checking will occur
         // when the safe type is constructed.
         safe_convert(10, 17); // runtime cost in creating parameters