diff --git a/packages/perseus/src/perseus-types.ts b/packages/perseus/src/perseus-types.ts
index a8962f5714..dfa6d60844 100644
--- a/packages/perseus/src/perseus-types.ts
+++ b/packages/perseus/src/perseus-types.ts
@@ -1116,7 +1116,7 @@ export type PerseusNumericInputAnswer = {
     // Translatable Display; A description for why this answer is correct, wrong, or ungraded
     message: string;
     // The expected answer
-    value: number;
+    value?: number;
     // Whether this answer is "correct", "wrong", or "ungraded"
     status: string;
     // The forms available for this answer.  Options: "integer, ""decimal", "proper", "improper", "mixed", or "pi"
diff --git a/packages/perseus/src/util/parse-perseus-json/perseus-parsers/numeric-input-widget.ts b/packages/perseus/src/util/parse-perseus-json/perseus-parsers/numeric-input-widget.ts
index 8b4d36d31b..47bb471c13 100644
--- a/packages/perseus/src/util/parse-perseus-json/perseus-parsers/numeric-input-widget.ts
+++ b/packages/perseus/src/util/parse-perseus-json/perseus-parsers/numeric-input-widget.ts
@@ -32,7 +32,7 @@ export const parseNumericInputWidget: Parser<NumericInputWidget> = parseWidget(
         answers: array(
             object({
                 message: string,
-                value: number,
+                value: optional(number),
                 status: string,
                 answerForms: optional(array(parseMathFormat)),
                 strict: boolean,
diff --git a/packages/perseus/src/util/parse-perseus-json/regression-tests/data/numeric-input-answer-without-value.json b/packages/perseus/src/util/parse-perseus-json/regression-tests/data/numeric-input-answer-without-value.json
new file mode 100644
index 0000000000..0ef7538a66
--- /dev/null
+++ b/packages/perseus/src/util/parse-perseus-json/regression-tests/data/numeric-input-answer-without-value.json
@@ -0,0 +1,115 @@
+{
+  "question": {
+    "content": "$\\bigg(\\dfrac{2}{3} \\bigg)^3 =$ [[☃ expression 1]]",
+    "images": {},
+    "widgets": {
+      "numeric-input 1": {
+        "type": "numeric-input",
+        "alignment": "default",
+        "static": false,
+        "graded": true,
+        "options": {
+          "answers": [
+            {
+              "status": "correct",
+              "message": "",
+              "simplify": "required",
+              "strict": false,
+              "maxError": null,
+              "answerForms": [
+                "proper",
+                "improper"
+              ]
+            }
+          ],
+          "size": "normal",
+          "coefficient": false,
+          "labelText": "",
+          "rightAlign": false,
+          "static": false,
+          "multipleNumberInput": false
+        },
+        "version": {
+          "major": 0,
+          "minor": 0
+        }
+      },
+      "expression 1": {
+        "options": {
+          "answerForms": [
+            {
+              "considered": "correct",
+              "form": true,
+              "key": 0,
+              "simplify": true,
+              "value": "\\frac{8}{27}",
+              "times": false,
+              "functions": [
+                "f",
+                "g",
+                "h"
+              ],
+              "buttonSets": [
+                "basic"
+              ],
+              "buttonsVisible": "focused",
+              "linterContext": {
+                "contentType": "",
+                "highlightLint": false,
+                "paths": [],
+                "stack": []
+              }
+            }
+          ],
+          "times": false,
+          "buttonSets": [
+            "basic"
+          ],
+          "functions": [
+            "f",
+            "g",
+            "h"
+          ],
+          "static": false
+        },
+        "type": "expression",
+        "version": {
+          "major": 1,
+          "minor": 0
+        },
+        "graded": true,
+        "alignment": "default",
+        "static": false
+      }
+    }
+  },
+  "answerArea": {
+    "calculator": false,
+    "chi2Table": false,
+    "financialCalculatorMonthlyPayment": false,
+    "financialCalculatorTotalAmount": false,
+    "financialCalculatorTimeToPayOff": false,
+    "periodicTable": false,
+    "periodicTableWithKey": false,
+    "tTable": false,
+    "zTable": false
+  },
+  "itemDataVersion": {
+    "major": 0,
+    "minor": 1
+  },
+  "hints": [
+    {
+      "replace": false,
+      "content": "$\\bigg(\\dfrac{2}{3} \\bigg)^3 =\\dfrac{2}{3}\\times \\dfrac{2}{3}\\times\\dfrac{2}{3}$\n\nLet's perform this multiplication to find the answer.",
+      "images": {},
+      "widgets": {}
+    },
+    {
+      "replace": false,
+      "content": "On multiplying, we see that\n\n$\\dfrac{2}{3}\\times \\dfrac{2}{3}\\times\\dfrac{2}{3}=\\boxed{\\dfrac{8}{27}}$.",
+      "images": {},
+      "widgets": {}
+    }
+  ]
+}
diff --git a/packages/perseus/src/widgets/numeric-input/score-numeric-input.test.ts b/packages/perseus/src/widgets/numeric-input/score-numeric-input.test.ts
index c6ee90ec2c..13ce2a6cb1 100644
--- a/packages/perseus/src/widgets/numeric-input/score-numeric-input.test.ts
+++ b/packages/perseus/src/widgets/numeric-input/score-numeric-input.test.ts
@@ -287,6 +287,121 @@ describe("static function validate", () => {
         // Assert - "incomplete"
         expect(score).toHaveBeenAnsweredCorrectly();
     });
+
+    it("ignores missing values when determining if the answer can be formatted as a percentage", () => {
+        const rubric: PerseusNumericInputRubric = {
+            answers: [
+                {
+                    // This answer is missing its value field.
+                    status: "correct",
+                    maxError: 0,
+                    simplify: "",
+                    strict: false,
+                    message: "",
+                },
+                {
+                    // This is the actual correct answer
+                    value: 0.5,
+                    status: "correct",
+                    maxError: 0,
+                    simplify: "",
+                    strict: false,
+                    message: "",
+                },
+            ],
+            coefficient: true,
+        };
+
+        const score = scoreNumericInput({currentValue: "50%"}, rubric, mockStrings);
+
+        expect(score).toHaveBeenAnsweredCorrectly();
+    })
+
+    it("converts a percentage input value to a decimal", () => {
+        const rubric: PerseusNumericInputRubric = {
+            answers: [
+                {
+                    value: 0.2,
+                    status: "correct",
+                    maxError: 0,
+                    simplify: "",
+                    strict: false,
+                    message: "",
+                },
+            ],
+            coefficient: true,
+        };
+
+        const score = scoreNumericInput({currentValue: "20%"}, rubric, mockStrings);
+
+        expect(score).toHaveBeenAnsweredCorrectly();
+    });
+
+    it("rejects percentages greater than 100%", () => {
+        // TODO(benchristel): This seems like incorrect behavior. I've added
+        // this test to characterize the current behavior. Feel free to
+        // delete/change it if it's in your way.
+        const rubric: PerseusNumericInputRubric = {
+            answers: [
+                {
+                    value: 1.2,
+                    status: "correct",
+                    maxError: 0,
+                    simplify: "",
+                    strict: false,
+                    message: "",
+                },
+            ],
+            coefficient: true,
+        };
+
+        const score = scoreNumericInput({currentValue: "120%"}, rubric, mockStrings);
+
+        expect(score).toHaveBeenAnsweredIncorrectly();
+    });
+
+    it("accepts answers with an extra, incorrect percent sign if > 1", () => {
+        // TODO(benchristel): This seems like incorrect behavior. I've added
+        // this test to characterize the current behavior. Feel free to
+        // delete/change it if it's in your way.
+        const rubric: PerseusNumericInputRubric = {
+            answers: [
+                {
+                    value: 1.1,
+                    status: "correct",
+                    maxError: 0,
+                    simplify: "",
+                    strict: false,
+                    message: "",
+                },
+            ],
+            coefficient: true,
+        };
+
+        const score = scoreNumericInput({currentValue: "1.1%"}, rubric, mockStrings);
+
+        expect(score).toHaveBeenAnsweredCorrectly();
+    });
+
+    it("rejects answers with an extra, incorrect percent sign if < 1", () => {
+        const rubric: PerseusNumericInputRubric = {
+            answers: [
+                {
+                    value: 0.9,
+                    status: "correct",
+                    maxError: 0,
+                    simplify: "",
+                    strict: false,
+                    message: "",
+                },
+            ],
+            coefficient: true,
+        };
+
+        const score = scoreNumericInput({currentValue: "0.9%"}, rubric, mockStrings);
+
+        expect(score).toHaveBeenAnsweredIncorrectly();
+    });
 });
 
 describe("maybeParsePercentInput utility function", () => {
diff --git a/packages/perseus/src/widgets/numeric-input/score-numeric-input.ts b/packages/perseus/src/widgets/numeric-input/score-numeric-input.ts
index 46a98eaf12..256c2b021b 100644
--- a/packages/perseus/src/widgets/numeric-input/score-numeric-input.ts
+++ b/packages/perseus/src/widgets/numeric-input/score-numeric-input.ts
@@ -111,7 +111,7 @@ function scoreNumericInput(
 
     const normalizedAnswerExpected = rubric.answers
         .filter((answer) => answer.status === "correct")
-        .every((answer) => Math.abs(answer.value) <= 1);
+        .every((answer) => answer.value == null || Math.abs(answer.value) <= 1);
 
     // The coefficient is an attribute of the widget
     let localValue: string | number = currentValue;