diff --git a/build.gradle b/build.gradle
index 7733484..36fd331 100644
--- a/build.gradle
+++ b/build.gradle
@@ -14,6 +14,7 @@ repositories {
 }
 
 dependencies {
+    compile 'com.moandjiezana.toml:toml4j:0.7.1'
     testCompile 'junit:junit:4.12'
 }
 
diff --git a/src/org/nwapw/abacus/Abacus.java b/src/org/nwapw/abacus/Abacus.java
index 3343d71..eacc0d8 100644
--- a/src/org/nwapw/abacus/Abacus.java
+++ b/src/org/nwapw/abacus/Abacus.java
@@ -1,46 +1,188 @@
 package org.nwapw.abacus;
 
-import org.nwapw.abacus.plugin.PluginManager;
-//import org.nwapw.abacus.plugin.StandardPlugin;
-import org.nwapw.abacus.plugin.StandardPlugin;
-import org.nwapw.abacus.window.Window;
+import org.nwapw.abacus.config.ConfigurationObject;
+import org.nwapw.abacus.function.Operator;
+import org.nwapw.abacus.number.NaiveNumber;
+import org.nwapw.abacus.number.NumberInterface;
 import org.nwapw.abacus.plugin.ClassFinder;
+import org.nwapw.abacus.plugin.PluginListener;
+import org.nwapw.abacus.plugin.PluginManager;
+import org.nwapw.abacus.plugin.StandardPlugin;
+import org.nwapw.abacus.tree.NumberReducer;
+import org.nwapw.abacus.tree.TreeBuilder;
+import org.nwapw.abacus.tree.TreeNode;
+import org.nwapw.abacus.window.Window;
 
 import javax.swing.*;
+import java.io.File;
 import java.io.IOException;
-import java.util.ArrayList;
+import java.lang.reflect.InvocationTargetException;
 
-public class Abacus {
+/**
+ * The main calculator class. This is responsible
+ * for piecing together all of the components, allowing
+ * their interaction with each other.
+ */
+public class Abacus implements PluginListener {
 
+    /**
+     * The default implementation to use for the number representation.
+     */
+    public static final Class<? extends NumberInterface> DEFAULT_NUMBER = NaiveNumber.class;
+    /**
+     * The file used for saving and loading configuration.
+     */
+    public static final File CONFIG_FILE = new File("config.toml");
+
+    /**
+     * The main Abacus UI.
+     */
     private Window mainUi;
-    private PluginManager manager;
+    /**
+     * The plugin manager responsible for
+     * loading and unloading plugins,
+     * and getting functions from them.
+     */
+    private PluginManager pluginManager;
+    /**
+     * Tree builder built from plugin manager,
+     * used to construct parse trees.
+     */
+    private TreeBuilder treeBuilder;
+    /**
+     * The reducer used to evaluate the tree.
+     */
+    private NumberReducer numberReducer;
+    /**
+     * The configuration loaded from a file.
+     */
+    private ConfigurationObject configuration;
 
+    /**
+     * Creates a new instance of the Abacus calculator.
+     */
     public Abacus(){
-        init();
+        pluginManager = new PluginManager(this);
+        mainUi = new Window(this);
+        numberReducer = new NumberReducer(this);
+        configuration = new ConfigurationObject(CONFIG_FILE);
+        configuration.save(CONFIG_FILE);
+
+        pluginManager.addListener(this);
+        pluginManager.addInstantiated(new StandardPlugin(pluginManager));
+        try {
+            ClassFinder.loadJars("plugins")
+                    .forEach(plugin -> pluginManager.addClass(plugin));
+        } catch (IOException | ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+        pluginManager.load();
+
+        mainUi.setVisible(true);
     }
 
-    private void init() {
+    /**
+     * Gets the current tree builder.
+     * @return the main tree builder in this abacus instance.
+     */
+    public TreeBuilder getTreeBuilder() {
+        return treeBuilder;
+    }
+
+    /**
+     * Gets the current plugin manager,
+     * @return the plugin manager in this abacus instance.
+     */
+    public PluginManager getPluginManager() {
+        return pluginManager;
+    }
+
+    /**
+     * Gets the current UI.
+     * @return the UI window in this abacus instance.
+     */
+    public Window getMainUi() {
+        return mainUi;
+    }
+
+    /**
+     * Get the reducer that is responsible for transforming
+     * an expression into a number.
+     * @return the number reducer in this abacus instance.
+     */
+    public NumberReducer getNumberReducer() {
+        return numberReducer;
+    }
+
+    /**
+     * Gets the configuration object associated with this instance.
+     * @return the configuration object.
+     */
+    public ConfigurationObject getConfiguration() {
+        return configuration;
+    }
+
+    /**
+     * Parses a string into a tree structure using the main
+     * tree builder.
+     * @param input the input string to parse
+     * @return the resulting tree, null if the tree builder or the produced tree are null.
+     */
+    public TreeNode parseString(String input){
+        if(treeBuilder == null) return null;
+        return treeBuilder.fromString(input);
+    }
+
+    /**
+     * Evaluates the given tree using the main
+     * number reducer.
+     * @param tree the tree to reduce, must not be null.
+     * @return the resulting number, or null of the reduction failed.
+     */
+    public NumberInterface evaluateTree(TreeNode tree){
+        return tree.reduce(numberReducer);
+    }
+
+    public NumberInterface numberFromString(String numberString){
+        Class<? extends NumberInterface> toInstantiate =
+                pluginManager.numberFor(configuration.getNumberImplementation());
+        if(toInstantiate == null) toInstantiate = DEFAULT_NUMBER;
+
+        try {
+            return toInstantiate.getConstructor(String.class).newInstance(numberString);
+        } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    @Override
+    public void onLoad(PluginManager manager) {
+        treeBuilder = new TreeBuilder(this);
+        for(String function : manager.getAllFunctions()){
+            treeBuilder.registerFunction(function);
+        }
+        for(String operator : manager.getAllOperators()){
+            Operator operatorObject = manager.operatorFor(operator);
+            treeBuilder.registerOperator(operator,
+                    operatorObject.getAssociativity(),
+                    operatorObject.getType(),
+                    operatorObject.getPrecedence());
+        }
+    }
+
+    @Override
+    public void onUnload(PluginManager manager) {
+        treeBuilder = null;
+    }
+
+    public static void main(String[] args){
         try {
             UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
         } catch (ClassNotFoundException | InstantiationException | UnsupportedLookAndFeelException | IllegalAccessException e) {
             e.printStackTrace();
         }
-        manager = new PluginManager();
-        manager.addInstantiated(new StandardPlugin(manager));
-        try {
-            ClassFinder.loadJars("plugins")
-                    .forEach(plugin -> manager.addClass(plugin));
-        } catch (IOException | ClassNotFoundException e) {
-            e.printStackTrace();
-        }
-        mainUi = new Window(manager);
-        mainUi.setVisible(true);
-        manager.load();
 
-    }
-
-    public static void main(String[] args){
         new Abacus();
     }
-
 }
diff --git a/src/org/nwapw/abacus/config/Configuration.java b/src/org/nwapw/abacus/config/Configuration.java
new file mode 100644
index 0000000..2039d60
--- /dev/null
+++ b/src/org/nwapw/abacus/config/Configuration.java
@@ -0,0 +1,14 @@
+package org.nwapw.abacus.config;
+
+/**
+ * Serializable class that will be used to load TOML
+ * configurations.
+ */
+public class Configuration {
+
+    /**
+     * The type of number this calculator should use.
+     */
+    public String numberType;
+
+}
diff --git a/src/org/nwapw/abacus/config/ConfigurationObject.java b/src/org/nwapw/abacus/config/ConfigurationObject.java
new file mode 100644
index 0000000..1f0c066
--- /dev/null
+++ b/src/org/nwapw/abacus/config/ConfigurationObject.java
@@ -0,0 +1,105 @@
+package org.nwapw.abacus.config;
+
+import com.moandjiezana.toml.Toml;
+import com.moandjiezana.toml.TomlWriter;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * A configuration object, which essentially
+ * manages saving, loading, and getting values
+ * from the configuration. While Configuration is
+ * the data model, this is the interface with it.
+ */
+public class ConfigurationObject {
+
+    /**
+     * The writer used to store the configuration.
+     */
+    private static final TomlWriter TOML_WRITER = new TomlWriter();
+    /**
+     * The configuration instance being modeled.
+     */
+    private Configuration configuration;
+
+    /**
+     * Sets up the ConfigurationObject.
+     * different constructors do different things,
+     * but they all lead here.
+     * @param configuration the configuration to set up with.
+     */
+    private void setup(Configuration configuration){
+        this.configuration = configuration;
+    }
+
+    /**
+     * Creates a default configuration.
+     * @return the newly created default configuration.
+     */
+    private Configuration getDefaultConfig(){
+        configuration = new Configuration();
+        configuration.numberType = "naive";
+        return configuration;
+    }
+
+    /**
+     * Returns the implementation the user has requested to
+     * represent their numbers.
+     * @return the implementation name.
+     */
+    public String getNumberImplementation() {
+        return configuration.numberType;
+    }
+
+    /**
+     * Saves the ConfigurationObject to the given file.
+     * @param toFile the file to save ot.
+     * @return true if the save succeed, false if otherwise.
+     */
+    public boolean save(File toFile){
+        if(toFile.getParentFile() != null) toFile.getParentFile().mkdirs();
+        try {
+            TOML_WRITER.write(configuration, toFile);
+            return true;
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return false;
+    }
+
+    /**
+     * Creates a new configuration object with the given config.
+     * @param config the config to use.
+     */
+    public ConfigurationObject(Configuration config){
+        setup(config);
+    }
+
+    /**
+     * Create a configuration object by attempting to
+     * load a config from the given path, using the
+     * default configuration otherwise.
+     * @param path the path to attempt to load.
+     */
+    public ConfigurationObject(File path){
+        Configuration config;
+        if(!path.exists()) {
+            config = getDefaultConfig();
+        } else {
+            Toml parse = new Toml();
+            parse.read(path);
+            config = parse.to(Configuration.class);
+        }
+        setup(config);
+    }
+
+    /**
+     * Creates a new configuration object with the
+     * default configuration.
+     */
+    public ConfigurationObject(){
+        setup(getDefaultConfig());
+    }
+
+}
diff --git a/src/org/nwapw/abacus/number/NaiveNumber.java b/src/org/nwapw/abacus/number/NaiveNumber.java
index 1a80cd1..96e42dd 100755
--- a/src/org/nwapw/abacus/number/NaiveNumber.java
+++ b/src/org/nwapw/abacus/number/NaiveNumber.java
@@ -10,6 +10,13 @@ public class NaiveNumber implements NumberInterface {
      */
     private double value;
 
+    /**
+     * Creates a new NaiveNumber with the given string.
+     * @param value the value, which will be parsed as a double.
+     */
+    public NaiveNumber(String value) {
+        this(Double.parseDouble(value));
+    }
     /**
      * Creates a new NaiveNumber with the given value.
      * @param value the value to use.
@@ -28,7 +35,7 @@ public class NaiveNumber implements NumberInterface {
     public static final NaiveNumber ONE = new NaiveNumber(1);
 
     @Override
-    public int precision() {
+    public int getMaxPrecision() {
         return 18;
     }
 
diff --git a/src/org/nwapw/abacus/number/NumberInterface.java b/src/org/nwapw/abacus/number/NumberInterface.java
index f425a30..1f87d11 100755
--- a/src/org/nwapw/abacus/number/NumberInterface.java
+++ b/src/org/nwapw/abacus/number/NumberInterface.java
@@ -6,10 +6,10 @@ package org.nwapw.abacus.number;
 public interface NumberInterface {
 
     /**
-     * The precision to which this number operates.
+     * The maximum precision to which this number operates.
      * @return the precision.
      */
-    int precision();
+    int getMaxPrecision();
 
     /**
      * Multiplies this number by another, returning
diff --git a/src/org/nwapw/abacus/number/PreciseNumber.java b/src/org/nwapw/abacus/number/PreciseNumber.java
index 1641cff..8b01622 100755
--- a/src/org/nwapw/abacus/number/PreciseNumber.java
+++ b/src/org/nwapw/abacus/number/PreciseNumber.java
@@ -1,8 +1,6 @@
 package org.nwapw.abacus.number;
 
 import java.math.BigDecimal;
-import java.math.BigInteger;
-import java.math.MathContext;
 import java.math.RoundingMode;
 
 public class PreciseNumber implements NumberInterface{
@@ -43,7 +41,7 @@ public class PreciseNumber implements NumberInterface{
     }
 
     @Override
-    public int precision() {
+    public int getMaxPrecision() {
         return 54;
     }
 
@@ -54,7 +52,7 @@ public class PreciseNumber implements NumberInterface{
 
     @Override
     public NumberInterface divide(NumberInterface divisor) {
-        return new PreciseNumber(value.divide(((PreciseNumber) divisor).value, this.precision(), RoundingMode.HALF_UP));
+        return new PreciseNumber(value.divide(((PreciseNumber) divisor).value, this.getMaxPrecision(), RoundingMode.HALF_UP));
     }
 
     @Override
@@ -109,7 +107,7 @@ public class PreciseNumber implements NumberInterface{
 
     @Override
     public String toString() {
-        BigDecimal rounded = value.setScale(precision() - 4, RoundingMode.HALF_UP);
+        BigDecimal rounded = value.setScale(getMaxPrecision() - 4, RoundingMode.HALF_UP);
         return rounded.stripTrailingZeros().toPlainString();
     }
 }
diff --git a/src/org/nwapw/abacus/plugin/Plugin.java b/src/org/nwapw/abacus/plugin/Plugin.java
index 1f57b1d..2bf4a2d 100644
--- a/src/org/nwapw/abacus/plugin/Plugin.java
+++ b/src/org/nwapw/abacus/plugin/Plugin.java
@@ -2,6 +2,7 @@ package org.nwapw.abacus.plugin;
 
 import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.function.Operator;
+import org.nwapw.abacus.number.NumberInterface;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -24,6 +25,10 @@ public abstract class Plugin {
      * A hash map of operators mapped to their string names.
      */
     private Map<String, Operator> operators;
+    /**
+     * A hash map of operators mapped to their string names.
+     */
+    private Map<String, Class<? extends NumberInterface>> numbers;
     /**
      * The plugin manager in which to search for functions
      * not inside this package,
@@ -44,6 +49,7 @@ public abstract class Plugin {
         this.manager = manager;
         functions = new HashMap<>();
         operators = new HashMap<>();
+        numbers = new HashMap<>();
         enabled = false;
     }
 
@@ -63,6 +69,14 @@ public abstract class Plugin {
         return operators.keySet();
     }
 
+    /**
+     * Gets the list of all numbers provided by this plugin.
+     * @return the list of registered numbers.
+     */
+    public final Set<String> providedNumbers(){
+        return numbers.keySet();
+    }
+
     /**
      * Gets a function under the given function name.
      * @param functionName the name of the function to get
@@ -81,6 +95,15 @@ public abstract class Plugin {
         return operators.get(operatorName);
     }
 
+    /**
+     * Gets the class under the given name.
+     * @param numberName the name of the class.
+     * @return the class, or null if the plugin doesn't provide it.
+     */
+    public final Class<? extends NumberInterface> getNumber(String numberName){
+        return numbers.get(numberName);
+    }
+
     /**
      * Enables the function, loading the necessary instances
      * of functions.
@@ -124,6 +147,18 @@ public abstract class Plugin {
         operators.put(name, operator);
     }
 
+    /**
+     * To be used in load(). Registers a number class
+     * with the plugin internally, which makes it possible
+     * for the user to select it as an "implementation" for the
+     * number that they would like to use.
+     * @param name the name to register it under.
+     * @param toRegister the class to register.
+     */
+    protected final void registerNumber(String name, Class<? extends NumberInterface> toRegister){
+        numbers.put(name, toRegister);
+    }
+
     /**
      * Searches the PluginManager for the given function name.
      * This can be used by the plugins internally in order to call functions
diff --git a/src/org/nwapw/abacus/plugin/PluginManager.java b/src/org/nwapw/abacus/plugin/PluginManager.java
index 8bb3879..33af14a 100644
--- a/src/org/nwapw/abacus/plugin/PluginManager.java
+++ b/src/org/nwapw/abacus/plugin/PluginManager.java
@@ -1,7 +1,9 @@
 package org.nwapw.abacus.plugin;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.function.Operator;
+import org.nwapw.abacus.number.NumberInterface;
 
 import java.lang.reflect.InvocationTargetException;
 import java.util.*;
@@ -26,10 +28,15 @@ public class PluginManager {
      */
     private Map<String, Function> cachedFunctions;
     /**
-     * List of operators tha have been cached,
+     * List of operators that have been cached,
      * that is, found in a plugin and returned.
      */
     private Map<String, Operator> cachedOperators;
+    /**
+     * List of registered number implementations that have
+     * been cached, that is, found in a plugin and returned.
+     */
+    private Map<String, Class<? extends NumberInterface>> cachedNumbers;
     /**
      * List of all functions loaded by the plugins.
      */
@@ -38,21 +45,33 @@ public class PluginManager {
      * List of all operators loaded by the plugins.
      */
     private Set<String> allOperators;
+    /**
+     * List of all numbers loaded by the plugins.
+     */
+    private Set<String> allNumbers;
     /**
      * The list of plugin listeners attached to this instance.
      */
     private Set<PluginListener> listeners;
+    /**
+     * The instance of Abacus that is used to interact with its other
+     * components.
+     */
+    private Abacus abacus;
 
     /**
      * Creates a new plugin manager.
      */
-    public PluginManager(){
+    public PluginManager(Abacus abacus){
+        this.abacus = abacus;
         loadedPluginClasses = new HashSet<>();
         plugins = new HashSet<>();
         cachedFunctions = new HashMap<>();
         cachedOperators = new HashMap<>();
+        cachedNumbers = new HashMap<>();
         allFunctions = new HashSet<>();
         allOperators = new HashSet<>();
+        allNumbers = new HashSet<>();
         listeners = new HashSet<>();
     }
 
@@ -104,6 +123,15 @@ public class PluginManager {
         return searchCached(plugins, cachedOperators, Plugin::providedOperators, Plugin::getOperator, name);
     }
 
+    /**
+     * Gets a numer implementation under the given name.
+     * @param name the name of the implementation.
+     * @return the implementation class
+     */
+    public Class<? extends NumberInterface> numberFor(String name){
+        return searchCached(plugins, cachedNumbers, Plugin::providedNumbers, Plugin::getNumber, name);
+    }
+
     /**
      * Adds an instance of Plugin that already has been instantiated.
      * @param plugin the plugin to add.
@@ -136,6 +164,7 @@ public class PluginManager {
         for(Plugin plugin : plugins){
             allFunctions.addAll(plugin.providedFunctions());
             allOperators.addAll(plugin.providedOperators());
+            allNumbers.addAll(plugin.providedNumbers());
         }
         listeners.forEach(e -> e.onLoad(this));
     }
@@ -147,6 +176,7 @@ public class PluginManager {
         for(Plugin plugin : plugins) plugin.disable();
         allFunctions.clear();
         allOperators.clear();
+        allNumbers.clear();
         listeners.forEach(e -> e.onUnload(this));
     }
 
@@ -174,6 +204,14 @@ public class PluginManager {
         return allOperators;
     }
 
+    /**
+     * Gets all the number implementations loaded by the Plugin Manager
+     * @return the set of all implementations that were loaded
+     */
+    public Set<String> getAllNumbers() {
+        return allNumbers;
+    }
+
     /**
      * Adds a plugin change listener to this plugin manager.
      * @param listener the listener to add.
diff --git a/src/org/nwapw/abacus/plugin/StandardPlugin.java b/src/org/nwapw/abacus/plugin/StandardPlugin.java
index 1ae0969..a0f234c 100755
--- a/src/org/nwapw/abacus/plugin/StandardPlugin.java
+++ b/src/org/nwapw/abacus/plugin/StandardPlugin.java
@@ -6,6 +6,7 @@ import org.nwapw.abacus.function.OperatorAssociativity;
 import org.nwapw.abacus.function.OperatorType;
 import org.nwapw.abacus.number.NaiveNumber;
 import org.nwapw.abacus.number.NumberInterface;
+import org.nwapw.abacus.number.PreciseNumber;
 
 import java.util.function.BiFunction;
 
@@ -21,6 +22,9 @@ public class StandardPlugin extends Plugin {
 
     @Override
     public void onEnable() {
+        registerNumber("naive", NaiveNumber.class);
+        registerNumber("precise", PreciseNumber.class);
+
         registerOperator("+", new Operator(OperatorAssociativity.LEFT, OperatorType.BINARY_INFIX, 0, new Function() {
             @Override
             protected boolean matchesParams(NumberInterface[] params) {
@@ -292,7 +296,7 @@ public class StandardPlugin extends Plugin {
      * @return the maximum error.
      */
     private NumberInterface getMaxError(NumberInterface number){
-        return (new NaiveNumber(10)).promoteTo(number.getClass()).intPow(-number.precision());
+        return (new NaiveNumber(10)).promoteTo(number.getClass()).intPow(-number.getMaxPrecision());
     }
 
 }
diff --git a/src/org/nwapw/abacus/tree/NumberReducer.java b/src/org/nwapw/abacus/tree/NumberReducer.java
index bb10a5e..6fcff47 100644
--- a/src/org/nwapw/abacus/tree/NumberReducer.java
+++ b/src/org/nwapw/abacus/tree/NumberReducer.java
@@ -1,8 +1,8 @@
 package org.nwapw.abacus.tree;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.Function;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.plugin.PluginManager;
 
 /**
  * A reducer implementation that turns a tree into a single number.
@@ -13,14 +13,14 @@ public class NumberReducer implements Reducer<NumberInterface> {
     /**
      * The plugin manager from which to draw the functions.
      */
-    private PluginManager manager;
+    private Abacus abacus;
 
     /**
-     * Creates a new number reducer with the given plugin manager.
-     * @param manager the plugin manager.
+     * Creates a new number reducer.
+     * @param abacus the calculator instance.
      */
-    public NumberReducer(PluginManager manager){
-        this.manager = manager;
+    public NumberReducer(Abacus abacus){
+        this.abacus = abacus;
     }
 
     @Override
@@ -30,12 +30,12 @@ public class NumberReducer implements Reducer<NumberInterface> {
         } else if(node instanceof BinaryInfixNode){
             NumberInterface left = (NumberInterface) children[0];
             NumberInterface right = (NumberInterface) children[1];
-            Function function = manager.operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
+            Function function = abacus.getPluginManager().operatorFor(((BinaryInfixNode) node).getOperation()).getFunction();
             if(function == null) return null;
             return function.apply(left, right);
         } else if(node instanceof UnaryPrefixNode) {
             NumberInterface child = (NumberInterface) children[0];
-            Function functionn = manager.operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
+            Function functionn = abacus.getPluginManager().operatorFor(((UnaryPrefixNode) node).getOperation()).getFunction();
             if(functionn == null) return null;
             return functionn.apply(child);
         } else if(node instanceof FunctionNode){
@@ -43,7 +43,7 @@ public class NumberReducer implements Reducer<NumberInterface> {
             for(int i = 0; i < convertedChildren.length; i++){
                 convertedChildren[i] = (NumberInterface) children[i];
             }
-            Function function = manager.functionFor(((FunctionNode) node).getFunction());
+            Function function = abacus.getPluginManager().functionFor(((FunctionNode) node).getFunction());
             if(function == null) return null;
             return function.apply(convertedChildren);
         }
diff --git a/src/org/nwapw/abacus/tree/TreeBuilder.java b/src/org/nwapw/abacus/tree/TreeBuilder.java
index 83f2ebd..97800e4 100644
--- a/src/org/nwapw/abacus/tree/TreeBuilder.java
+++ b/src/org/nwapw/abacus/tree/TreeBuilder.java
@@ -1,12 +1,11 @@
 package org.nwapw.abacus.tree;
 
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.function.OperatorAssociativity;
 import org.nwapw.abacus.function.OperatorType;
 import org.nwapw.abacus.lexing.Lexer;
 import org.nwapw.abacus.lexing.pattern.Match;
 import org.nwapw.abacus.lexing.pattern.Pattern;
-import org.nwapw.abacus.number.NaiveNumber;
-import org.nwapw.abacus.number.PreciseNumber;
 
 import java.util.*;
 
@@ -31,6 +30,11 @@ public class TreeBuilder {
      * The map of operator types.
      */
     private Map<String, OperatorType> typeMap;
+    /**
+     * The abacus instance required to interact with
+     * other components of the calculator.
+     */
+    private Abacus abacus;
 
     /**
      * Comparator used to sort token types.
@@ -40,7 +44,8 @@ public class TreeBuilder {
     /**
      * Creates a new TreeBuilder.
      */
-    public TreeBuilder(){
+    public TreeBuilder(Abacus abacus){
+        this.abacus = abacus;
         lexer = new Lexer<TokenType>(){{
             register(" ", TokenType.WHITESPACE);
             register(",", TokenType.COMMA);
@@ -172,7 +177,7 @@ public class TreeBuilder {
                 else return new UnaryPrefixNode(operator, applyTo);
             }
         } else if(matchType == TokenType.NUM){
-            return new NumberNode(new NaiveNumber(Double.parseDouble(source.substring(match.getFrom(), match.getTo()))));
+            return new NumberNode(abacus.numberFromString(source.substring(match.getFrom(), match.getTo())));
         } else if(matchType == TokenType.FUNCTION){
             String functionName = source.substring(match.getFrom(), match.getTo());
             FunctionNode node = new FunctionNode(functionName);
diff --git a/src/org/nwapw/abacus/window/Window.java b/src/org/nwapw/abacus/window/Window.java
index 0e7a95e..0484cf2 100644
--- a/src/org/nwapw/abacus/window/Window.java
+++ b/src/org/nwapw/abacus/window/Window.java
@@ -1,11 +1,7 @@
 package org.nwapw.abacus.window;
 
-import org.nwapw.abacus.function.Operator;
+import org.nwapw.abacus.Abacus;
 import org.nwapw.abacus.number.NumberInterface;
-import org.nwapw.abacus.plugin.PluginListener;
-import org.nwapw.abacus.plugin.PluginManager;
-import org.nwapw.abacus.tree.NumberReducer;
-import org.nwapw.abacus.tree.TreeBuilder;
 import org.nwapw.abacus.tree.TreeNode;
 
 import javax.swing.*;
@@ -18,7 +14,7 @@ import java.awt.event.MouseEvent;
 /**
  * The main UI window for the calculator.
  */
-public class Window extends JFrame implements PluginListener {
+public class Window extends JFrame {
 
     private static final String CALC_STRING = "Calculate";
     private static final String SYNTAX_ERR_STRING = "Syntax Error";
@@ -47,18 +43,10 @@ public class Window extends JFrame implements PluginListener {
     };
 
     /**
-     * The plugin manager used to retrieve functions.
+     * The instance of the Abacus class, used
+     * for interaction with plugins and configuration.
      */
-    private PluginManager manager;
-    /**
-     * The builder used to construct the parse trees.
-     */
-    private TreeBuilder builder;
-    /**
-     * The reducer used to evaluate the tree.
-     */
-    private NumberReducer reducer;
-
+    private Abacus abacus;
     /**
      * The last output by the calculator.
      */
@@ -130,15 +118,14 @@ public class Window extends JFrame implements PluginListener {
      * Action listener that causes the input to be evaluated.
      */
     private ActionListener evaluateListener = (event) -> {
-        if(builder == null) return;
-        TreeNode parsedExpression = builder.fromString(inputField.getText());
+        TreeNode parsedExpression = abacus.parseString(inputField.getText());
         if(parsedExpression == null){
             lastOutputArea.setText(SYNTAX_ERR_STRING);
             return;
         }
-        NumberInterface numberInterface = parsedExpression.reduce(reducer);
-        if(numberInterface == null){
-            lastOutputArea.setText(EVAL_ERR_STRING);;
+        NumberInterface numberInterface = abacus.evaluateTree(parsedExpression);
+        if(numberInterface == null) {
+            lastOutputArea.setText(EVAL_ERR_STRING);
             return;
         }
         lastOutput = numberInterface.toString();
@@ -159,13 +146,11 @@ public class Window extends JFrame implements PluginListener {
 
     /**
      * Creates a new window with the given manager.
-     * @param manager the manager to use.
+     * @param abacus the calculator instance to interact with other components.
      */
-    public Window(PluginManager manager){
+    public Window(Abacus abacus){
         this();
-        this.manager = manager;
-        manager.addListener(this);
-        reducer = new NumberReducer(manager);
+        this.abacus = abacus;
     }
 
     /**
@@ -261,23 +246,4 @@ public class Window extends JFrame implements PluginListener {
         });
     }
 
-    @Override
-    public void onLoad(PluginManager manager) {
-        builder = new TreeBuilder();
-        for(String function : manager.getAllFunctions()){
-            builder.registerFunction(function);
-        }
-        for(String operator : manager.getAllOperators()){
-            Operator operatorObject = manager.operatorFor(operator);
-            builder.registerOperator(operator,
-                    operatorObject.getAssociativity(),
-                    operatorObject.getType(),
-                    operatorObject.getPrecedence());
-        }
-    }
-
-    @Override
-    public void onUnload(PluginManager manager) {
-        builder = null;
-    }
 }