Show equals button preferences

calculatorpp/res/values/text_preferences.xml

@@ -3,5 +3,5 @@
     <string name="c_auto_orientation_summary">If turned on calculator will change screen orientation automatically</string>
 
     <string name="c_show_equals_button_title">Show equals button</string>
-    <string name="c_show_equals_button_summary">Preference hides or shows equals button</string>
+    <string name="c_show_equals_button_summary">If turned on equals button is shown</string>
 </resources>

calculatorpp/res/xml/preferences.xml

@@ -139,7 +139,14 @@
                 a:key="autoOrientation"
                 a:title="@string/c_auto_orientation_title"
                 a:summary="@string/c_auto_orientation_summary"
-                a:defaultValue="false"/>
+                a:defaultValue="true"/>
+
+
+        <android.preference.CheckBoxPreference
+                a:key="showEqualsButton"
+                a:title="@string/c_show_equals_button_title"
+                a:summary="@string/c_show_equals_button_summary"
+                a:defaultValue="true"/>
 
 	</PreferenceScreen>