diff --git a/utils/answer-types.js b/utils/answer-types.js
index 24b599dfe..77ca34c0e 100644
--- a/utils/answer-types.js
+++ b/utils/answer-types.js
@@ -1103,6 +1103,7 @@ Khan.answerTypes = $.extend(Khan.answerTypes, {
                     message: null,
                     guess: guess
                 };
+                var blockGradingMessage = null;
 
                 // If the answer is completely empty, don't grade it
                 if (checkIfAnswerEmpty(guess)) {
@@ -1117,27 +1118,36 @@ Khan.answerTypes = $.extend(Khan.answerTypes, {
                     // with the corresponding validator
                     var pass = validators[i](g);
 
-                    score.empty = score.empty && pass.empty;
-                    score.correct = score.correct && pass.correct;
-                    // TODO(eater): This just forwards one message
-                    if (pass.message) {
-                        score.message = pass.message;
+                    if (pass.message && pass.empty) {
                         // Special case where a validator returns a message
                         // for an "empty" response. This probably means it's
                         // not really empty, but a correct-but-not-simplified
                         // answer. Rather that treating this as actually empty,
                         // possibly leading to the entire multiple being marked
-                        // wrong for being incomplete, bail here and forward on
-                        // the message.
-                        if (pass.empty) {
-                            score.empty = true;
-                            score.correct = false;
-                            return score;
-                        }
+                        // wrong for being incomplete, note the situation but
+                        // continue determining whether the entire answer is
+                        // otherwise correct or not before forwarding on the
+                        // message.
+                        blockGradingMessage = pass.message;
+                    } else {
+                        score.empty = score.empty && pass.empty;
+                        score.correct = score.correct && pass.correct;
+                        // TODO(eater): This just forwards one message
+                        score.message = pass.message;
                     }
                 });
 
-                return score;
+                if (blockGradingMessage == null || !score.correct) {
+                    score.empty = false;
+                    return score;
+                } else {
+                    return {
+                        empty: true,
+                        correct: false,
+                        message: blockGradingMessage,
+                        guess: guess
+                    };
+                }
             };
         }
     },
@@ -1255,6 +1265,8 @@ Khan.answerTypes = $.extend(Khan.answerTypes, {
                     message: null,
                     guess: guess
                 };
+                var blockGradingMessage = null;
+
                 // Store a copy of each of the validators. If one correctly
                 // identifies a guess, remove it from this array, so duplicate
                 // answers aren't marked correct twice
@@ -1269,6 +1281,19 @@ Khan.answerTypes = $.extend(Khan.answerTypes, {
                     $.each(unusedValidators, function(i, validator) {
                         var pass = validator(g);
 
+                        // If this validator is trying to block grading
+                        if (pass.empty && pass.message) {
+                            // remove the working validator
+                            unusedValidators.splice(i, 1);
+                            // We want to block the entire answer from being
+                            // accepted as correct but continue checking in
+                            // case another part is wrong.
+                            blockGradingMessage = pass.message;
+                            correct = true;
+                            // break
+                            return false;
+                        }
+
                         // If this validator completely accepts this answer
                         // or returns a check answer message
                         if (pass.correct || pass.message) {
@@ -1322,7 +1347,16 @@ Khan.answerTypes = $.extend(Khan.answerTypes, {
                     score.correct = false;
                 }
 
-                return score;
+                if (blockGradingMessage == null || !score.correct) {
+                    return score;
+                } else {
+                    return {
+                        empty: true,
+                        correct: false,
+                        message: blockGradingMessage,
+                        guess: guess
+                    };
+                }
             };
         }
     },
diff --git a/utils/test/answer-types.html b/utils/test/answer-types.html
index db5336417..d7f0c449c 100644
--- a/utils/test/answer-types.html
+++ b/utils/test/answer-types.html
@@ -43,7 +43,7 @@
         };
     </script>
     <script src="../../local-only/underscore.js"></script>
-    <script src="../../third_party/MathJax/2.1/MathJax.js?config=KAthJax-da9a7f53e588f3837b045a600e1dc439"></script>
+    <script src="../../third_party/MathJax/2.1/MathJax.js?config=KAthJax-9e2776ffe7d2006f16f36d0d55d9464b"></script>
     <script src="../../local-only/katex/katex.js"></script>
 
     <!-- Include QUnit -->
@@ -396,21 +396,6 @@ <h2 id="qunit-userAgent"></h2>
         start();
     });
 
-    asyncTest("number decimal percent", 9, function() {
-        var $problem = jQuery("#qunit-fixture .problem").append(
-            "<p class='solution' data-type='number' data-forms='decimal, percent'>0.42<\/p>"
-        );
-
-        var answerData = Khan.answerTypes.number.setup($("#solutionarea"),
-                $problem.children(".solution"));
-
-        testAnswer(answerData, "0.42", "right", "right answer is right");
-        testAnswer(answerData, "42%", "right", "right answer is right");
-        testAnswer(answerData, "42", "empty-message", "leaving off percent sign provides a message");
-
-        start();
-    });
-
     asyncTest("number mixed", 18, function() {
         var $problem = jQuery("#qunit-fixture .problem").append(
             "<p class='solution' data-type='number' data-forms='mixed'>-1.5<\/p>"
@@ -636,7 +621,7 @@ <h2 id="qunit-userAgent"></h2>
         start();
     });
 
-    asyncTest("multiple", 21, function() {
+    asyncTest("multiple", 42, function() {
         var $problem = jQuery("#qunit-fixture .problem").append(
             "<p class='solution' data-type='multiple'>" +
                 "<span class='sol'>7<\/span>" +
@@ -654,6 +639,13 @@ <h2 id="qunit-userAgent"></h2>
         testMultipleAnswer(answerData, ["", "3/2"], "wrong", "incomplete answer is wrong");
         testMultipleAnswer(answerData, ["", ""], "empty", "empty answer is empty");
         testMultipleAnswer(answerData, ["7", "6/4"], "empty-message", "unsimplified right answer provides a message");
+        testMultipleAnswer(answerData, ["14/2", "6/4"], "empty-message", "unsimplified right gives message");
+        testMultipleAnswer(answerData, ["14/2", "3/2"], "empty-message", "unsimplified right gives message");
+        testMultipleAnswer(answerData, ["7", "6/4"], "empty-message", "unsimplified right gives message");
+        testMultipleAnswer(answerData, ["14/2", "7"], "wrong", "unsimplified right and wrong is wrong");
+        testMultipleAnswer(answerData, ["3", "6/4"], "wrong", "unsimplified right and wrong is wrong");
+        testMultipleAnswer(answerData, ["4/2", "4/2"], "wrong", "unsimplified wrong is wrong");
+        testMultipleAnswer(answerData, ["14/2", ""], "wrong", "unsimplified imcomplete answer is wrong");
 
         start();
     });
@@ -862,7 +854,7 @@ <h2 id="qunit-userAgent"></h2>
         start();
     });
 
-    asyncTest("set with as many things", 24, function() {
+    asyncTest("set with as many things", 45, function() {
         var $problem = jQuery("#qunit-fixture .problem").append(
             "<div class='solution' data-type='set'>" +
                 "<span class='set-sol'>12<\/span>" +
@@ -885,6 +877,13 @@ <h2 id="qunit-userAgent"></h2>
         testMultipleAnswer(answerData, ["", ""], "empty", "empty answer is empty");
         testMultipleAnswer(answerData, ["12", "14"], "wrong", "wrong answer is wrong");
         testMultipleAnswer(answerData, ["12", "12"], "wrong", "wrong answer is wrong");
+        testMultipleAnswer(answerData, ["24/2", "26/2"], "empty-message", "unsimplified right gives message");
+        testMultipleAnswer(answerData, ["24/2", "13"], "empty-message", "unsimplified right gives message");
+        testMultipleAnswer(answerData, ["12", "26/2"], "empty-message", "unsimplified right gives message");
+        testMultipleAnswer(answerData, ["24/2", "14"], "wrong", "unsimplified right and wrong is wrong");
+        testMultipleAnswer(answerData, ["14", "26/2"], "wrong", "unsimplified right and wrong is wrong");
+        testMultipleAnswer(answerData, ["4/2", "4/2"], "wrong", "unsimplified wrong is wrong");
+        testMultipleAnswer(answerData, ["24/2", ""], "wrong", "unsimplified imcomplete answer is wrong");
 
         start();
     });
diff --git a/utils/test/rational_expressions.html b/utils/test/rational_expressions.html
index 2b254e9b9..7c2750d2e 100644
--- a/utils/test/rational_expressions.html
+++ b/utils/test/rational_expressions.html
@@ -38,7 +38,7 @@
         };
     </script>
     <script src="../../local-only/underscore.js"></script>
-    <script src="../MathJax/2.1/MathJax.js?config=KAthJax-da9a7f53e588f3837b045a600e1dc439"></script>
+    <script src="../MathJax/2.1/MathJax.js?config=KAthJax-9e2776ffe7d2006f16f36d0d55d9464b"></script>
 
     <!-- Include QUnit -->
     <link rel="stylesheet" href="../../test/qunit/qunit/qunit.css" type="text/css" media="screen">