diff --git a/res/layout/calc_subtraction_button.xml b/res/layout/calc_subtraction_button.xml
index d5030359..2feda812 100644
--- a/res/layout/calc_subtraction_button.xml
+++ b/res/layout/calc_subtraction_button.xml
@@ -8,7 +8,9 @@
 <org.solovyev.android.view.widgets.DirectionDragButton xmlns:a="http://schemas.android.com/apk/res/android"
 													   xmlns:calc="http://schemas.android.com/apk/res/org.solovyev.android.calculator"
 													   a:id="@+id/subtractionButton"
+													   calc:textUp="+…%"
 													   a:text="-"
+													   calc:textDown="-…%"
 													   calc:directionTextScale="0.5"
 													   style="?digitButtonStyle"
 													   a:onClick="digitButtonClickHandler"/>
\ No newline at end of file
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorModel.java b/src/main/java/org/solovyev/android/calculator/CalculatorModel.java
index 8d354f52..c0fa7aac 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorModel.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorModel.java
@@ -256,22 +256,30 @@ public enum CalculatorModel implements CursorControl, HistoryControl<CalculatorH
 
 				@Override
 				public void doOperation(@NotNull EditText editor) {
-
-					final MathType.Result mathType = MathType.getType(text, 0);
-
 					int cursorPositionOffset = 0;
+					final StringBuilder textToBeInserted = new StringBuilder();
 
-					final StringBuilder textToBeInserted = new StringBuilder(text);
-					switch (mathType.getMathType()) {
-						case function:
-							textToBeInserted.append("()");
-							cursorPositionOffset = -1;
-							break;
-					}
+					if (text.equals("+…%")) {
+						textToBeInserted .append("+%");
+						cursorPositionOffset = -1;
+					} else if (text.equals("-…%")) {
+						textToBeInserted.append("-%");
+						cursorPositionOffset = -1;
+					} else {
+						textToBeInserted.append(text);
 
-					if (cursorPositionOffset == 0) {
-						if ( MathType.openGroupSymbols.contains(text) ) {
-							cursorPositionOffset = -1;
+						final MathType.Result mathType = MathType.getType(text, 0);
+						switch (mathType.getMathType()) {
+							case function:
+								textToBeInserted.append("()");
+								cursorPositionOffset = -1;
+								break;
+						}
+
+						if (cursorPositionOffset == 0) {
+							if (MathType.openGroupSymbols.contains(text)) {
+								cursorPositionOffset = -1;
+							}
 						}
 					}
 
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java
index a3143c24..e5d0c8b4 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java
@@ -301,7 +301,7 @@ public class CalculatorVarsActivity extends ListActivity {
 
 		if (!StringUtils.isEmpty(name)) {
 			try {
-				Identifier.parser.parse(name, new MutableInt(0), 0);
+				Identifier.parser.parse(name, new MutableInt(0), 0, null);
 				result = true;
 			} catch (ParseException e) {
 				// not valid name;