diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
index 0b5f3654..79334e7e 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
@@ -23,7 +23,7 @@ import android.widget.TextView;
 import bsh.EvalError;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.solovyev.android.calculator.model.CalculatorModel;
+import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.view.FontSizeAdjuster;
 import org.solovyev.android.view.widgets.*;
 import org.solovyev.common.BooleanMapper;
@@ -73,7 +73,7 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 
 		firstTimeInit(preferences);
 
-		calculatorView = CalculatorView.instance.init(this, preferences, CalculatorModel.instance);
+		calculatorView = CalculatorView.instance.init(this, preferences, CalculatorEngine.instance);
 
 		dpclRegister.clear();
 
@@ -90,7 +90,7 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 		((DragButton) findViewById(R.id.leftButton)).setOnDragListener(toPositionOnDragListener);
 		dpclRegister.addListener(toPositionOnDragListener);
 
-		CalculatorModel.instance.reset(this, preferences);
+		CalculatorEngine.instance.reset(this, preferences);
 
 		preferences.registerOnSharedPreferenceChangeListener(this);
 	}
@@ -157,7 +157,7 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	private synchronized void firstTimeInit(@NotNull SharedPreferences preferences) {
 		if (!initialized) {
 			try {
-				CalculatorModel.instance.init(this, preferences);
+				CalculatorEngine.instance.init(this, preferences);
 			} catch (EvalError evalError) {
 				throw new RuntimeException("Could not initialize interpreter!");
 			}
@@ -362,7 +362,7 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 			restart();
 		}
 
-		calculatorView = CalculatorView.instance.init(this, preferences, CalculatorModel.instance);
+		calculatorView = CalculatorView.instance.init(this, preferences, CalculatorEngine.instance);
 
 		this.calculatorView.evaluate();
 	}
@@ -371,7 +371,7 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	public void onSharedPreferenceChanged(SharedPreferences preferences, @Nullable String s) {
 		dpclRegister.announce().onDragPreferencesChange(SimpleOnDragListener.getPreferences(preferences, this));
 
-		CalculatorModel.instance.reset(this, preferences);
+		CalculatorEngine.instance.reset(this, preferences);
 
 		final Boolean colorExpressionsInBracketsDefault = new BooleanMapper().parseValue(this.getString(R.string.p_calc_color_display));
 		assert colorExpressionsInBracketsDefault != null;
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java
index 8d9281ea..67b32919 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorVarsActivity.java
@@ -18,7 +18,7 @@ import android.widget.*;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.math.MathType;
-import org.solovyev.android.calculator.model.CalculatorModel;
+import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.calculator.model.Var;
 import org.solovyev.android.calculator.model.VarsRegister;
 import org.solovyev.common.utils.StringUtils;
@@ -45,7 +45,7 @@ public class CalculatorVarsActivity extends ListActivity {
 
 		setContentView(R.layout.vars);
 
-		adapter = new VarsArrayAdapter(this, R.layout.var, R.id.var_text, new ArrayList<Var>(CalculatorModel.instance.getVarsRegister().getVars()));
+		adapter = new VarsArrayAdapter(this, R.layout.var, R.id.var_text, new ArrayList<Var>(CalculatorEngine.instance.getVarsRegister().getVars()));
 		setListAdapter(adapter);
 
 		final ListView lv = getListView();
@@ -191,7 +191,7 @@ public class CalculatorVarsActivity extends ListActivity {
 				String description = editDescription.getText().toString();
 
 
-				final VarsRegister varsRegister = CalculatorModel.instance.getVarsRegister();
+				final VarsRegister varsRegister = CalculatorEngine.instance.getVarsRegister();
 				if (!StringUtils.isEmpty(name)) {
 					final Var varFromRegister = varsRegister.getVar(name);
 					if (varFromRegister == null || varFromRegister == editedInstance) {
@@ -334,7 +334,7 @@ public class CalculatorVarsActivity extends ListActivity {
 				builder.create().show();
 			} else {
 				adapter.remove(var);
-				final VarsRegister varsRegister = CalculatorModel.instance.getVarsRegister();
+				final VarsRegister varsRegister = CalculatorEngine.instance.getVarsRegister();
 				varsRegister.remove(var);
 				varsRegister.save(CalculatorVarsActivity.this);
 				CalculatorVarsActivity.this.adapter.notifyDataSetChanged();
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorView.java b/src/main/java/org/solovyev/android/calculator/CalculatorView.java
index eb537210..cd41d26c 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorView.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorView.java
@@ -19,7 +19,7 @@ import bsh.EvalError;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.math.MathType;
-import org.solovyev.android.calculator.model.CalculatorModel;
+import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.calculator.model.ParseException;
 import org.solovyev.android.view.CursorControl;
 import org.solovyev.android.view.HistoryControl;
@@ -47,10 +47,10 @@ public enum CalculatorView implements CursorControl, HistoryControl<CalculatorHi
 	private CalculatorDisplay display;
 
 	@NotNull
-	private CalculatorModel calculatorModel;
+	private CalculatorEngine calculatorEngine;
 
-	public CalculatorView init(@NotNull final Activity activity, @NotNull SharedPreferences preferences, @NotNull CalculatorModel calculator) {
-		this.calculatorModel = calculator;
+	public CalculatorView init(@NotNull final Activity activity, @NotNull SharedPreferences preferences, @NotNull CalculatorEngine calculator) {
+		this.calculatorEngine = calculator;
 
 		this.editor = (CalculatorEditor) activity.findViewById(R.id.calculatorEditor);
 
@@ -174,7 +174,7 @@ public enum CalculatorView implements CursorControl, HistoryControl<CalculatorHi
 		if (!StringUtils.isEmpty(expression)) {
 			try {
 				Log.d(CalculatorView.class.getName(), "Trying to evaluate: " + expression /*+ StringUtils.fromStackTrace(Thread.currentThread().getStackTrace())*/);
-				localDisplay.setText(calculatorModel.evaluate(JsclOperation.numeric, expression));
+				localDisplay.setText(calculatorEngine.evaluate(JsclOperation.numeric, expression));
 			} catch (EvalError e) {
 				handleEvaluationException(expression, localDisplay, e);
 			} catch (ParseException e) {
diff --git a/src/main/java/org/solovyev/android/calculator/math/MathType.java b/src/main/java/org/solovyev/android/calculator/math/MathType.java
index a1671d31..34a86703 100644
--- a/src/main/java/org/solovyev/android/calculator/math/MathType.java
+++ b/src/main/java/org/solovyev/android/calculator/math/MathType.java
@@ -8,7 +8,7 @@ package org.solovyev.android.calculator.math;
 import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.calculator.CharacterAtPositionFinder;
 import org.solovyev.android.calculator.StartsWithFinder;
-import org.solovyev.android.calculator.model.CalculatorModel;
+import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.common.utils.Finder;
 
 import java.util.Arrays;
@@ -123,7 +123,7 @@ public enum MathType {
 			return new Result(MathType.function, foundString);
 		}
 
-		foundString = get(CalculatorModel.instance.getVarsRegister().getVarNames(), stringStartWithFinder);
+		foundString = get(CalculatorEngine.instance.getVarsRegister().getVarNames(), stringStartWithFinder);
 		if (foundString != null) {
 			return new Result(MathType.constant, foundString);
 		}
diff --git a/src/main/java/org/solovyev/android/calculator/model/CalculatorModel.java b/src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java
similarity index 96%
rename from src/main/java/org/solovyev/android/calculator/model/CalculatorModel.java
rename to src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java
index 3d0f71bd..cc14d9af 100644
--- a/src/main/java/org/solovyev/android/calculator/model/CalculatorModel.java
+++ b/src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java
@@ -20,7 +20,7 @@ import org.solovyev.common.NumberMapper;
  * Time: 11:38 PM
  */
 
-public enum CalculatorModel {
+public enum CalculatorEngine {
 
 	instance;
 
@@ -50,7 +50,7 @@ public enum CalculatorModel {
 
 			sb.append(preprocessor.process(expression));
 
-			//Log.d(CalculatorModel.class.getName(), "Preprocessed expression: " + preprocessedExpression);
+			//Log.d(CalculatorEngine.class.getName(), "Preprocessed expression: " + preprocessedExpression);
 
 			final Object evaluationObject = interpreter.eval(ToJsclTextProcessor.wrap(operation, sb.toString()));
 
diff --git a/src/main/java/org/solovyev/android/calculator/model/FromJsclTextProcessor.java b/src/main/java/org/solovyev/android/calculator/model/FromJsclTextProcessor.java
index 497b2c6f..2071e515 100644
--- a/src/main/java/org/solovyev/android/calculator/model/FromJsclTextProcessor.java
+++ b/src/main/java/org/solovyev/android/calculator/model/FromJsclTextProcessor.java
@@ -80,6 +80,6 @@ class FromJsclTextProcessor implements TextProcessor {
 
 	private Double round(@NotNull String result) {
 		final Double dResult = Double.valueOf(result);
-		return MathUtils.round(dResult, CalculatorModel.instance.getNumberOfFractionDigits());
+		return MathUtils.round(dResult, CalculatorEngine.instance.getNumberOfFractionDigits());
 	}
 }
diff --git a/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java b/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java
index ba18ddb2..675fbe13 100644
--- a/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java
+++ b/src/main/java/org/solovyev/android/calculator/model/ToJsclTextProcessor.java
@@ -71,9 +71,9 @@ class ToJsclTextProcessor implements TextProcessor {
 			int offset = 0;
 			String functionName = CollectionsUtils.get(MathType.prefixFunctions, startsWithFinder);
 			if (functionName == null) {
-				String varName = CollectionsUtils.get(CalculatorModel.instance.getVarsRegister().getVarNames(), startsWithFinder);
+				String varName = CollectionsUtils.get(CalculatorEngine.instance.getVarsRegister().getVarNames(), startsWithFinder);
 				if (varName != null) {
-					final Var var = CalculatorModel.instance.getVarsRegister().getVar(varName);
+					final Var var = CalculatorEngine.instance.getVarsRegister().getVar(varName);
 					if (var != null) {
 						result.append(var.getValue());
 						offset = varName.length();
@@ -96,7 +96,7 @@ class ToJsclTextProcessor implements TextProcessor {
 	}
 
 	private void replaceVariables(StringBuilder sb, String s, int i, @NotNull StartsWithFinder startsWithFinder) {
-		for (Var var : CalculatorModel.instance.getVarsRegister().getVars()) {
+		for (Var var : CalculatorEngine.instance.getVarsRegister().getVars()) {
 			if (!var.isSystem()) {
 				if (s.startsWith(var.getName(), i)) {
 					if (CollectionsUtils.get(MathType.prefixFunctions, startsWithFinder) == null) {
diff --git a/src/test/java/org/solovyev/android/calculator/math/MathTypeTest.java b/src/test/java/org/solovyev/android/calculator/math/MathTypeTest.java
index bef479fd..7cdb2aae 100644
--- a/src/test/java/org/solovyev/android/calculator/math/MathTypeTest.java
+++ b/src/test/java/org/solovyev/android/calculator/math/MathTypeTest.java
@@ -9,7 +9,7 @@ package org.solovyev.android.calculator.math;
 import junit.framework.Assert;
 import org.junit.BeforeClass;
 import org.junit.Test;
-import org.solovyev.android.calculator.model.CalculatorModel;
+import org.solovyev.android.calculator.model.CalculatorEngine;
 
 /**
  * User: serso
@@ -20,7 +20,7 @@ public class MathTypeTest {
 
 	@BeforeClass
 	public static void setUp() throws Exception {
-		CalculatorModel.instance.init(null, null);
+		CalculatorEngine.instance.init(null, null);
 	}
 
 	@Test
diff --git a/src/test/java/org/solovyev/android/calculator/model/CalculatorModelTest.java b/src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java
similarity index 91%
rename from src/test/java/org/solovyev/android/calculator/model/CalculatorModelTest.java
rename to src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java
index 1b8fac85..73e885bb 100644
--- a/src/test/java/org/solovyev/android/calculator/model/CalculatorModelTest.java
+++ b/src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java
@@ -17,16 +17,16 @@ import org.solovyev.android.calculator.JsclOperation;
  * Date: 9/17/11
  * Time: 9:47 PM
  */
-public class CalculatorModelTest {
+public class CalculatorEngineTest {
 
 	@BeforeClass
 	public static void setUp() throws Exception {
-		CalculatorModel.instance.init(null, null);
+		CalculatorEngine.instance.init(null, null);
 	}
 
 	@Test
 	public void testEvaluate() throws Exception {
-		final CalculatorModel cm = CalculatorModel.instance;
+		final CalculatorEngine cm = CalculatorEngine.instance;
 
 		Assert.assertEquals("4.0", cm.evaluate(JsclOperation.numeric, "2+2"));
 		Assert.assertEquals("-0.7568", cm.evaluate(JsclOperation.numeric, "sin(4)"));
@@ -62,7 +62,7 @@ public class CalculatorModelTest {
 		}
 		Assert.assertEquals("0.73909", cm.evaluate(JsclOperation.numeric, "cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(cos(1))))))))))))))))))))))))))))))))))))"));
 
-		CalculatorModel.instance.getVarsRegister().addVar(null, new Var.Builder("si", 5d));
+		CalculatorEngine.instance.getVarsRegister().addVar(null, new Var.Builder("si", 5d));
 		Assert.assertEquals("5.0", cm.evaluate(JsclOperation.numeric, "si"));
 		try {
 			cm.evaluate(JsclOperation.numeric, "sin");
@@ -75,11 +75,11 @@ public class CalculatorModelTest {
 		Assert.assertEquals("-23.97311", cm.evaluate(JsclOperation.numeric, "si*sin(5)si"));
 		Assert.assertEquals("-3.30879", cm.evaluate(JsclOperation.numeric, "sisin(5si)si"));
 
-		CalculatorModel.instance.getVarsRegister().addVar(null, new Var.Builder("s", 1d));
+		CalculatorEngine.instance.getVarsRegister().addVar(null, new Var.Builder("s", 1d));
 		Assert.assertEquals("5.0", cm.evaluate(JsclOperation.numeric, "si"));
 
-		CalculatorModel.instance.getVarsRegister().addVar(null, new Var.Builder("k", 3.5d));
-		CalculatorModel.instance.getVarsRegister().addVar(null, new Var.Builder("k1", 4d));
+		CalculatorEngine.instance.getVarsRegister().addVar(null, new Var.Builder("k", 3.5d));
+		CalculatorEngine.instance.getVarsRegister().addVar(null, new Var.Builder("k1", 4d));
 		Assert.assertEquals("4.0", cm.evaluate(JsclOperation.numeric, "k11"));
 	}
 
diff --git a/src/test/java/org/solovyev/android/calculator/model/ToJsclTextProcessorTest.java b/src/test/java/org/solovyev/android/calculator/model/ToJsclTextProcessorTest.java
index 7685a1b4..6f92077e 100644
--- a/src/test/java/org/solovyev/android/calculator/model/ToJsclTextProcessorTest.java
+++ b/src/test/java/org/solovyev/android/calculator/model/ToJsclTextProcessorTest.java
@@ -19,7 +19,7 @@ public class ToJsclTextProcessorTest {
 
 	@BeforeClass
 	public static void setUp() throws Exception {
-		CalculatorModel.instance.init(null, null);
+		CalculatorEngine.instance.init(null, null);
 	}
 
 	@Test