diff --git a/src/main/java/org/nwapw/abacus/function/Operator.java b/src/main/java/org/nwapw/abacus/function/Operator.java
index eceb179..b7352c4 100644
--- a/src/main/java/org/nwapw/abacus/function/Operator.java
+++ b/src/main/java/org/nwapw/abacus/function/Operator.java
@@ -26,6 +26,7 @@ public class Operator {
      * Creates a new operator with the given parameters.
      *
      * @param associativity the associativity of the operator.
+     * @param operatorType  the type of this operator, like binary infix or unary postfix.
      * @param precedence    the precedence of the operator.
      * @param function      the function that the operator calls.
      */
diff --git a/src/main/java/org/nwapw/abacus/lexing/pattern/ValueNode.java b/src/main/java/org/nwapw/abacus/lexing/pattern/ValueNode.java
index 4630d91..2daa7c9 100644
--- a/src/main/java/org/nwapw/abacus/lexing/pattern/ValueNode.java
+++ b/src/main/java/org/nwapw/abacus/lexing/pattern/ValueNode.java
@@ -15,7 +15,7 @@ public class ValueNode<T> extends PatternNode<T> {
     /**
      * Creates a new node that matches the given character.
      *
-     * @param value
+     * @param value the character value of the node.
      */
     public ValueNode(char value) {
         this.value = value;
diff --git a/src/main/java/org/nwapw/abacus/number/NumberInterface.java b/src/main/java/org/nwapw/abacus/number/NumberInterface.java
index e8ca571..835a335 100755
--- a/src/main/java/org/nwapw/abacus/number/NumberInterface.java
+++ b/src/main/java/org/nwapw/abacus/number/NumberInterface.java
@@ -82,14 +82,14 @@ public interface NumberInterface {
     /**
      * Returns the least integer greater than or equal to the number.
      *
-     * @return the least integer >= the number, if int can hold the value.
+     * @return the least integer bigger or equal to the number, if int can hold the value.
      */
     NumberInterface ceiling();
 
     /**
      * Return the greatest integer less than or equal to the number.
      *
-     * @return the greatest int >= the number, if int can hold the value.
+     * @return the greatest integer smaller or equal the number, if int can hold the value.
      */
     NumberInterface floor();
 
@@ -104,7 +104,7 @@ public interface NumberInterface {
      * Returns the integer representation of this number, discarding any fractional part,
      * if int can hold the value.
      *
-     * @return
+     * @return the integer value of this number.
      */
     int intValue();
 
diff --git a/src/main/java/org/nwapw/abacus/plugin/NumberImplementation.java b/src/main/java/org/nwapw/abacus/plugin/NumberImplementation.java
index 8ccbf75..319a78d 100644
--- a/src/main/java/org/nwapw/abacus/plugin/NumberImplementation.java
+++ b/src/main/java/org/nwapw/abacus/plugin/NumberImplementation.java
@@ -28,7 +28,7 @@ public abstract class NumberImplementation {
      * Creates a new number implementation with the given data.
      *
      * @param implementation the implementation class.
-     * @param priority       the priority, higher -> more likely to be converted into.
+     * @param priority       the priority, higher means more likely to be converted into.
      */
     public NumberImplementation(Class<? extends NumberInterface> implementation, int priority) {
         this.implementation = implementation;
diff --git a/src/main/java/org/nwapw/abacus/plugin/PluginManager.java b/src/main/java/org/nwapw/abacus/plugin/PluginManager.java
index a6899d8..b1e5143 100644
--- a/src/main/java/org/nwapw/abacus/plugin/PluginManager.java
+++ b/src/main/java/org/nwapw/abacus/plugin/PluginManager.java
@@ -70,6 +70,8 @@ public class PluginManager {
 
     /**
      * Creates a new plugin manager.
+     *
+     * @param abacus the abacus instance.
      */
     public PluginManager(Abacus abacus) {
         this.abacus = abacus;