diff --git a/core/field_angle.js b/core/field_angle.js
index c5534ff0e..be88c27f7 100644
--- a/core/field_angle.js
+++ b/core/field_angle.js
@@ -34,7 +34,7 @@ goog.require('goog.userAgent');
 /**
  * Class for an editable angle field.
  * @param {(string|number)=} opt_value The initial content of the field. The
- *     value should cast to a number, and if it does not, "0" will be used.
+ *     value should cast to a number, and if it does not, '0' will be used.
  * @param {Function=} opt_validator An optional function that is called
  *     to validate any constraints on what the user entered.  Takes the new
  *     text as an argument and returns the accepted text or null to abort
@@ -43,11 +43,11 @@ goog.require('goog.userAgent');
  * @constructor
  */
 Blockly.FieldAngle = function(opt_value, opt_validator) {
-  // Add degree symbol: "360°" (LTR) or "°360" (RTL)
+  // Add degree symbol: '360°' (LTR) or '°360' (RTL)
   this.symbol_ = Blockly.utils.createSvgElement('tspan', {}, null);
   this.symbol_.appendChild(document.createTextNode('\u00B0'));
 
-  opt_value = (opt_value && !isNaN(opt_value)) ? String(opt_value) : "0";
+  opt_value = (opt_value && !isNaN(opt_value)) ? String(opt_value) : '0';
   Blockly.FieldAngle.superClass_.constructor.call(
       this, opt_value, opt_validator);
 };
diff --git a/core/field_number.js b/core/field_number.js
index 6de97de0f..55daa477b 100644
--- a/core/field_number.js
+++ b/core/field_number.js
@@ -32,7 +32,7 @@ goog.require('goog.math');
 /**
  * Class for an editable number field.
  * @param {(string|number)=} value The initial content of the field. The value
- *     should cast to a number, and if it does not, "0" will be used.
+ *     should cast to a number, and if it does not, '0' will be used.
  * @param {(string|number)=} opt_min Minimum value.
  * @param {(string|number)=} opt_max Maximum value.
  * @param {(string|number)=} opt_precision Precision for value.
@@ -45,7 +45,7 @@ goog.require('goog.math');
  */
 Blockly.FieldNumber =
     function(opt_value, opt_min, opt_max, opt_precision, opt_validator) {
-  opt_value = (opt_value && !isNaN(opt_value)) ? String(opt_value) : "0";
+  opt_value = (opt_value && !isNaN(opt_value)) ? String(opt_value) : '0';
   Blockly.FieldNumber.superClass_.constructor.call(
       this, opt_value, opt_validator);
   this.setConstraints(opt_min, opt_max, opt_precision);
diff --git a/tests/jsunit/field_angle_test.js b/tests/jsunit/field_angle_test.js
index 7ffd1203f..e5646d96c 100644
--- a/tests/jsunit/field_angle_test.js
+++ b/tests/jsunit/field_angle_test.js
@@ -25,15 +25,15 @@
 'use strict';
 
 function test_fieldangle_constructor() {
-  assertEquals(new Blockly.FieldAngle().getValue(), "0");
-  assertEquals(new Blockly.FieldAngle(null).getValue(), "0");
-  assertEquals(new Blockly.FieldAngle(undefined).getValue(), "0");
-  assertEquals(new Blockly.FieldAngle(1).getValue(), "1");
-  assertEquals(new Blockly.FieldAngle(1.5).getValue(), "1.5");
-  assertEquals(new Blockly.FieldAngle("2").getValue(), "2");
-  assertEquals(new Blockly.FieldAngle("2.5").getValue(), "2.5");
+  assertEquals(new Blockly.FieldAngle().getValue(), '0');
+  assertEquals(new Blockly.FieldAngle(null).getValue(), '0');
+  assertEquals(new Blockly.FieldAngle(undefined).getValue(), '0');
+  assertEquals(new Blockly.FieldAngle(1).getValue(), '1');
+  assertEquals(new Blockly.FieldAngle(1.5).getValue(), '1.5');
+  assertEquals(new Blockly.FieldAngle('2').getValue(), '2');
+  assertEquals(new Blockly.FieldAngle('2.5').getValue(), '2.5');
 
   // Bad values
-  assertEquals(new Blockly.FieldAngle("bad").getValue(), "0");
-  assertEquals(new Blockly.FieldAngle(NaN).getValue(), "0");
+  assertEquals(new Blockly.FieldAngle('bad').getValue(), '0');
+  assertEquals(new Blockly.FieldAngle(NaN).getValue(), '0');
 }
diff --git a/tests/jsunit/field_number_test.js b/tests/jsunit/field_number_test.js
index 10764d43b..20f277036 100644
--- a/tests/jsunit/field_number_test.js
+++ b/tests/jsunit/field_number_test.js
@@ -27,22 +27,22 @@
 function test_fieldnumber_constructor() {
   // No arguments
   var field = new Blockly.FieldNumber();
-  assertEquals(field.getValue(), "0");
+  assertEquals(field.getValue(), '0');
   assertEquals(field.min_, -Infinity);
   assertEquals(field.max_, Infinity);
   assertEquals(field.precision_, 0);
 
   // Numeric values
   field = new Blockly.FieldNumber(1);
-  assertEquals(field.getValue(), "1");
+  assertEquals(field.getValue(), '1');
   field = new Blockly.FieldNumber(1.5);
-  assertEquals(field.getValue(), "1.5");
+  assertEquals(field.getValue(), '1.5');
 
   // String value
-  field = new Blockly.FieldNumber("2");
-  assertEquals(field.getValue(), "2");
-  field = new Blockly.FieldNumber("2.5");
-  assertEquals(field.getValue(), "2.5");
+  field = new Blockly.FieldNumber('2');
+  assertEquals(field.getValue(), '2');
+  field = new Blockly.FieldNumber('2.5');
+  assertEquals(field.getValue(), '2.5');
 
   // All values
   field = new Blockly.FieldNumber(
@@ -50,14 +50,14 @@ function test_fieldnumber_constructor() {
     /* min */ -128,
     /* max */ 127,
     /* precision */ 1);
-  assertEquals(field.getValue(), "0");
+  assertEquals(field.getValue(), '0');
   assertEquals(field.min_, -128);
   assertEquals(field.max_, 127);
   assertEquals(field.precision_, 1);
 
-  // Bad value defaults to "0"
-  field = new Blockly.FieldNumber("bad");
-  assertEquals(field.getValue(), "0");
+  // Bad value defaults to '0'
+  field = new Blockly.FieldNumber('bad');
+  assertEquals(field.getValue(), '0');
   field = new Blockly.FieldNumber(NaN);
-  assertEquals(field.getValue(), "0");
+  assertEquals(field.getValue(), '0');
 }