diff --git a/res/values-ru/strings.xml b/res/values-ru/strings.xml
index 7e5d5a91..bf20fde7 100644
--- a/res/values-ru/strings.xml
+++ b/res/values-ru/strings.xml
@@ -102,7 +102,14 @@
 	<string name="p_rad">Радианы</string>
 	<string name="p_grad">Грады</string>
 	<string name="p_turns">Обороты</string>
-	<string name="c_angle_units_summary">Определяет единицы измерения углов.</string>
+	<string name="c_angle_units_summary">Устанавливает единицы измерения углов.</string>
+
+	<string name="c_calc_numeral_bases">Системы счичления</string>
+	<string name="c_numeral_bases_summary">Устанавливает систему счисления для всех вводимых чисел.</string>
+	<string name="p_dec">Десятичная</string>
+	<string name="p_hex">Шестнадцатеричная</string>
+	<string name="p_oct">Восьмиричная</string>
+	<string name="p_bin">Бинарная</string>
 
 	<string name="c_calc_theme">Тема оформления</string>
 	<string name="p_default_theme">По умолчанию</string>
diff --git a/res/values/arrays.xml b/res/values/arrays.xml
index 889dad94..83dd1ce1 100644
--- a/res/values/arrays.xml
+++ b/res/values/arrays.xml
@@ -60,4 +60,17 @@
 		<item>turns</item>
 	</string-array>
 
+	<string-array name="p_numeral_bases_names">
+		<item>@string/p_dec</item>
+		<item>@string/p_hex</item>
+		<item>@string/p_oct</item>
+		<item>@string/p_bin</item>
+	</string-array>
+	<string-array name="p_numeral_bases">
+		<item>dec</item>
+		<item>hex</item>
+		<item>oct</item>
+		<item>bin</item>
+	</string-array>
+
 </resources>
\ No newline at end of file
diff --git a/res/values/default_values.xml b/res/values/default_values.xml
index e50b56ad..fb28c9bc 100644
--- a/res/values/default_values.xml
+++ b/res/values/default_values.xml
@@ -30,6 +30,9 @@
 	<string name="p_calc_angle_units_key">org.solovyev.android.calculator.CalculatorActivity_angle_units</string>
 	<string name="p_calc_angle_units">deg</string>
 
+	<string name="p_calc_numeral_bases_key">org.solovyev.android.calculator.CalculatorActivity_numeral_bases</string>
+	<string name="p_calc_numeral_bases">dec</string>
+
 	<string name="p_calc_theme_key">org.solovyev.android.calculator.CalculatorActivity_calc_theme</string>
 	<string name="p_calc_theme">default_theme</string>
 
diff --git a/res/values/strings.xml b/res/values/strings.xml
index aef26ab0..c55ab36c 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -105,6 +105,13 @@
 	<string name="p_turns">Turns</string>
 	<string name="c_angle_units_summary">Defines the default units for angles.</string>
 
+	<string name="c_calc_numeral_bases">Numeral systems</string>
+	<string name="c_numeral_bases_summary">Defines the default numeral system for all input numbers.</string>
+	<string name="p_dec">Decimal</string>
+	<string name="p_hex">Hexadecimal</string>
+	<string name="p_oct">Octal</string>
+	<string name="p_bin">Binary</string>
+
 	<string name="c_calc_theme">Theme</string>
 	<string name="p_default_theme">Default</string>
 	<string name="p_violet_theme">Violet</string>
diff --git a/res/xml/main_preferences.xml b/res/xml/main_preferences.xml
index ea7bd32c..ceb9c06e 100644
--- a/res/xml/main_preferences.xml
+++ b/res/xml/main_preferences.xml
@@ -29,6 +29,12 @@
 						a:summary="@string/c_angle_units_summary"
 						a:entryValues="@array/p_angle_units"/>
 
+		<ListPreference a:key="@string/p_calc_numeral_bases_key"
+						a:title="@string/c_calc_numeral_bases"
+						a:entries="@array/p_numeral_bases_names"
+						a:summary="@string/c_numeral_bases_summary"
+						a:entryValues="@array/p_numeral_bases"/>
+
 	</PreferenceCategory>
 
 
diff --git a/src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java b/src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java
index f98d89ac..ae689bbb 100644
--- a/src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java
+++ b/src/main/java/org/solovyev/android/calculator/model/CalculatorEngine.java
@@ -10,6 +10,7 @@ import android.content.SharedPreferences;
 import jscl.AngleUnit;
 import jscl.JsclMathEngine;
 import jscl.MathEngine;
+import jscl.NumeralBase;
 import jscl.math.Generic;
 import jscl.math.function.Function;
 import jscl.math.operator.Operator;
@@ -48,8 +49,12 @@ public enum CalculatorEngine {
 	public static final String RESULT_PRECISION_P_KEY = "org.solovyev.android.calculator.CalculatorModel_result_precision";
 	public static final String RESULT_PRECISION_DEFAULT = "5";
 
+	public static final String NUMERAL_BASES_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_numeral_bases";
+	public static final String NUMERAL_BASES_DEFAULT = "dec";
+
 	public static final String ANGLE_UNITS_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_angle_units";
 	public static final String ANGLE_UNITS_DEFAULT = "deg";
+
 	public static final int DEFAULT_TIMEOUT = 3000;
 
 	@NotNull
@@ -285,7 +290,8 @@ public enum CalculatorEngine {
 				//noinspection ConstantConditions
 				this.setPrecision(integerNumberMapper.parseValue(preferences.getString(RESULT_PRECISION_P_KEY, RESULT_PRECISION_DEFAULT)));
 				this.setRoundResult(preferences.getBoolean(ROUND_RESULT_P_KEY, ROUND_RESULT_DEFAULT));
-				this.setDefaultAngleUnits(AngleUnit.valueOf(preferences.getString(ANGLE_UNITS_P_KEY, ANGLE_UNITS_DEFAULT)));
+				this.setAngleUnits(AngleUnit.valueOf(preferences.getString(ANGLE_UNITS_P_KEY, ANGLE_UNITS_DEFAULT)));
+				this.setNumeralBase(NumeralBase.valueOf(preferences.getString(NUMERAL_BASES_P_KEY, NUMERAL_BASES_DEFAULT)));
 
 				final String groupingSeparator = preferences.getString(GROUPING_SEPARATOR_P_KEY, GROUPING_SEPARATOR_DEFAULT);
 				if (StringUtils.isEmpty(groupingSeparator)) {
@@ -337,10 +343,14 @@ public enum CalculatorEngine {
 		this.timeout = timeout;
 	}
 
-	public void setDefaultAngleUnits(@NotNull AngleUnit angleUnits) {
+	public void setAngleUnits(@NotNull AngleUnit angleUnits) {
 		getEngine().setAngleUnits(angleUnits);
 	}
 
+	public void setNumeralBase(@NotNull NumeralBase numeralBase) {
+		getEngine().setNumeralBase(numeralBase);
+	}
+
 	// for tests only
 	void setThreadKiller(@NotNull ThreadKiller threadKiller) {
 		this.threadKiller = threadKiller;
diff --git a/src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java b/src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java
index 1b606431..e8fdc727 100644
--- a/src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java
+++ b/src/main/java/org/solovyev/android/view/widgets/AngleUnitsButton.java
@@ -34,7 +34,7 @@ public class AngleUnitsButton extends DirectionDragButton {
 
 		if (result != null) {
 			final Resources resources = getResources();
-			if ( CalculatorEngine.instance.getEngine().getDefaultAngleUnit().name().equals(getDirectionText(direction)) ) {
+			if ( CalculatorEngine.instance.getEngine().getAngleUnits().name().equals(getDirectionText(direction)) ) {
 				result.setColor(resources.getColor(R.color.selected_angle_unit_text_color));
 			} else {
 				result.setColor(resources.getColor(R.color.default_text_color));