diff --git a/core/src/processing/data/FloatList.java b/core/src/processing/data/FloatList.java
index 1d06b772a..625850a1e 100644
--- a/core/src/processing/data/FloatList.java
+++ b/core/src/processing/data/FloatList.java
@@ -423,10 +423,13 @@ public class FloatList implements Iterable<Float> {
   }
 
 
-  private String exceptionText(int count, int index, String method){
-    return "The list size is "+count+". Trying to "+method+" the element at "+index+" which does not exist.";
+  private void boundsProblem(int index, String method) {
+    final String msg = String.format("The list size is %d. " +
+      "You cannot %s() to element %d.", count, method, index);
+    throw new ArrayIndexOutOfBoundsException(msg);
   }
 
+
   /**
    * @webref floatlist:method
    * @brief Add to a value
@@ -435,7 +438,7 @@ public class FloatList implements Iterable<Float> {
     if (index < count) {
       data[index] += amount;
     } else {
-      throw new ArrayIndexOutOfBoundsException(exceptionText(count, index, "add"));
+      boundsProblem(index, "add");
     }
   }
 
@@ -448,7 +451,7 @@ public class FloatList implements Iterable<Float> {
     if (index < count) {
       data[index] -= amount;
     } else {
-      throw new ArrayIndexOutOfBoundsException(exceptionText(count, index, "sub"));
+      boundsProblem(index, "sub");
     }
   }
 
@@ -461,7 +464,7 @@ public class FloatList implements Iterable<Float> {
     if (index < count) {
       data[index] *= amount;
     } else {
-      throw new ArrayIndexOutOfBoundsException(exceptionText(count, index, "mult"));
+      boundsProblem(index, "mult");
     }
   }
 
@@ -474,7 +477,7 @@ public class FloatList implements Iterable<Float> {
     if (index < count) {
       data[index] /= amount;
     } else {
-      throw new ArrayIndexOutOfBoundsException(exceptionText(count, index, "div"));
+      boundsProblem(index, "div");
     }
   }
 
diff --git a/core/src/processing/data/IntList.java b/core/src/processing/data/IntList.java
index 0cf5f207b..c591d3ae8 100644
--- a/core/src/processing/data/IntList.java
+++ b/core/src/processing/data/IntList.java
@@ -407,10 +407,14 @@ public class IntList implements Iterable<Integer> {
     data[index]++;
   }
 
-  private String exceptionText(int count, int index, String method){
-    return "The list size is "+count+". Trying to "+method+" the element at "+index+" which does not exist.";
+
+  private void boundsProblem(int index, String method) {
+    final String msg = String.format("The list size is %d. " +
+      "You cannot %s() to element %d.", count, method, index);
+    throw new ArrayIndexOutOfBoundsException(msg);
   }
 
+
   /**
    * @webref intlist:method
    * @brief Add to a value
@@ -419,7 +423,7 @@ public class IntList implements Iterable<Integer> {
     if (index < count) {
       data[index] += amount;
     } else {
-      throw new IndexOutOfBoundsException(exceptionText(count, index, "add"));
+      boundsProblem(index, "add");
     }
   }
 
@@ -431,7 +435,7 @@ public class IntList implements Iterable<Integer> {
     if (index < count) {
       data[index] -= amount;
     } else {
-      throw new IndexOutOfBoundsException(exceptionText(count, index, "sub"));
+      boundsProblem(index, "sub");
     }
   }
 
@@ -443,7 +447,7 @@ public class IntList implements Iterable<Integer> {
     if (index < count) {
       data[index] *= amount;
     } else {
-      throw new IndexOutOfBoundsException(exceptionText(count, index, "mult"));
+      boundsProblem(index, "mult");
     }
   }
 
@@ -455,7 +459,7 @@ public class IntList implements Iterable<Integer> {
     if (index < count) {
       data[index] /= amount;
     } else {
-      throw new IndexOutOfBoundsException(exceptionText(count, index, "div"));
+      boundsProblem(index, "div");
     }
   }
 
diff --git a/core/todo.txt b/core/todo.txt
index c14ac47e3..39592f074 100644
--- a/core/todo.txt
+++ b/core/todo.txt
@@ -11,6 +11,9 @@ X size(640,360 , P3D) doesn't work properly
 X   https://github.com/processing/processing/issues/2924
 X   https://github.com/processing/processing/issues/2925
 
+data
+X Add exceptions for FloatList and IntList when using add() w/o enough elements
+X   https://github.com/processing/processing/pull/3053
 
 applet/sketch
 X remove isGL(), is2D(), is3D(), displayable() from PApplet
@@ -107,6 +110,7 @@ _   but for NaN values, it's a necessity
 _ get() methods in List/Dict shouldn't allow you to get bad values
 _   but set() methods can automatically resize the arrays
 _   though that means insert() should allow you to insert past the end
+_   and should add/div/mult let you work on non-existent elements?
 _ addRow() is not efficient, probably need to do the doubling
 o   or have a setIncrement() function?
 _   it would default to 1 on tables loaded from a file