diff --git a/blocks/math.js b/blocks/math.js
index 4e87d5a7a..0350048c8 100644
--- a/blocks/math.js
+++ b/blocks/math.js
@@ -62,21 +62,35 @@ Blockly.Blocks['math_arithmetic'] = {
    * @this Blockly.Block
    */
   init: function() {
-    var OPERATORS =
-        [[Blockly.Msg.MATH_ADDITION_SYMBOL, 'ADD'],
-         [Blockly.Msg.MATH_SUBTRACTION_SYMBOL, 'MINUS'],
-         [Blockly.Msg.MATH_MULTIPLICATION_SYMBOL, 'MULTIPLY'],
-         [Blockly.Msg.MATH_DIVISION_SYMBOL, 'DIVIDE'],
-         [Blockly.Msg.MATH_POWER_SYMBOL, 'POWER']];
-    this.setHelpUrl(Blockly.Msg.MATH_ARITHMETIC_HELPURL);
-    this.setColour(Blockly.Blocks.math.HUE);
-    this.setOutput(true, 'Number');
-    this.appendValueInput('A')
-        .setCheck('Number');
-    this.appendValueInput('B')
-        .setCheck('Number')
-        .appendField(new Blockly.FieldDropdown(OPERATORS), 'OP');
-    this.setInputsInline(true);
+    this.jsonInit({
+      "message0": "%1 %2 %3",
+      "args0": [
+        {
+          "type": "input_value",
+          "name": "A",
+          "check": "Number"
+        },
+        {
+          "type": "field_dropdown",
+          "name": "OP",
+          "options":
+            [[Blockly.Msg.MATH_ADDITION_SYMBOL, 'ADD'],
+             [Blockly.Msg.MATH_SUBTRACTION_SYMBOL, 'MINUS'],
+             [Blockly.Msg.MATH_MULTIPLICATION_SYMBOL, 'MULTIPLY'],
+             [Blockly.Msg.MATH_DIVISION_SYMBOL, 'DIVIDE'],
+             [Blockly.Msg.MATH_POWER_SYMBOL, 'POWER']]
+        },
+        {
+          "type": "input_value",
+          "name": "B",
+          "check": "Number"
+        }
+      ],
+      "inputsInline": true,
+      "output": "Number",
+      "colour": Blockly.Blocks.math.HUE,
+      "helpUrl": Blockly.Msg.MATH_ARITHMETIC_HELPURL
+    });
     // Assign 'this' to a variable for use in the tooltip closure below.
     var thisBlock = this;
     this.setTooltip(function() {
@@ -99,20 +113,32 @@ Blockly.Blocks['math_single'] = {
    * @this Blockly.Block
    */
   init: function() {
-    var OPERATORS =
-        [[Blockly.Msg.MATH_SINGLE_OP_ROOT, 'ROOT'],
-         [Blockly.Msg.MATH_SINGLE_OP_ABSOLUTE, 'ABS'],
-         ['-', 'NEG'],
-         ['ln', 'LN'],
-         ['log10', 'LOG10'],
-         ['e^', 'EXP'],
-         ['10^', 'POW10']];
-    this.setHelpUrl(Blockly.Msg.MATH_SINGLE_HELPURL);
-    this.setColour(Blockly.Blocks.math.HUE);
-    this.setOutput(true, 'Number');
-    this.appendValueInput('NUM')
-        .setCheck('Number')
-        .appendField(new Blockly.FieldDropdown(OPERATORS), 'OP');
+    this.jsonInit({
+      "message0": "%1 %2",
+      "args0": [
+        {
+          "type": "field_dropdown",
+          "name": "OP",
+          "options": [
+            [Blockly.Msg.MATH_SINGLE_OP_ROOT, 'ROOT'],
+            [Blockly.Msg.MATH_SINGLE_OP_ABSOLUTE, 'ABS'],
+            ['-', 'NEG'],
+            ['ln', 'LN'],
+            ['log10', 'LOG10'],
+            ['e^', 'EXP'],
+            ['10^', 'POW10']
+          ]
+        },
+        {
+          "type": "input_value",
+          "name": "NUM",
+          "check": "Number"
+        }
+      ],
+      "output": "Number",
+      "colour": Blockly.Blocks.math.HUE,
+      "helpUrl": Blockly.Msg.MATH_SINGLE_HELPURL
+    });
     // Assign 'this' to a variable for use in the tooltip closure below.
     var thisBlock = this;
     this.setTooltip(function() {
@@ -137,19 +163,31 @@ Blockly.Blocks['math_trig'] = {
    * @this Blockly.Block
    */
   init: function() {
-    var OPERATORS =
-        [[Blockly.Msg.MATH_TRIG_SIN, 'SIN'],
-         [Blockly.Msg.MATH_TRIG_COS, 'COS'],
-         [Blockly.Msg.MATH_TRIG_TAN, 'TAN'],
-         [Blockly.Msg.MATH_TRIG_ASIN, 'ASIN'],
-         [Blockly.Msg.MATH_TRIG_ACOS, 'ACOS'],
-         [Blockly.Msg.MATH_TRIG_ATAN, 'ATAN']];
-    this.setHelpUrl(Blockly.Msg.MATH_TRIG_HELPURL);
-    this.setColour(Blockly.Blocks.math.HUE);
-    this.setOutput(true, 'Number');
-    this.appendValueInput('NUM')
-        .setCheck('Number')
-        .appendField(new Blockly.FieldDropdown(OPERATORS), 'OP');
+    this.jsonInit({
+      "message0": "%1 %2",
+      "args0": [
+        {
+          "type": "field_dropdown",
+          "name": "OP",
+          "options": [
+            [Blockly.Msg.MATH_TRIG_SIN, 'SIN'],
+            [Blockly.Msg.MATH_TRIG_COS, 'COS'],
+            [Blockly.Msg.MATH_TRIG_TAN, 'TAN'],
+            [Blockly.Msg.MATH_TRIG_ASIN, 'ASIN'],
+            [Blockly.Msg.MATH_TRIG_ACOS, 'ACOS'],
+            [Blockly.Msg.MATH_TRIG_ATAN, 'ATAN']
+          ]
+        },
+        {
+          "type": "input_value",
+          "name": "NUM",
+          "check": "Number"
+        }
+      ],
+      "output": "Number",
+      "colour": Blockly.Blocks.math.HUE,
+      "helpUrl": Blockly.Msg.MATH_TRIG_HELPURL
+    });
     // Assign 'this' to a variable for use in the tooltip closure below.
     var thisBlock = this;
     this.setTooltip(function() {
@@ -173,19 +211,27 @@ Blockly.Blocks['math_constant'] = {
    * @this Blockly.Block
    */
   init: function() {
-    var CONSTANTS =
-        [['\u03c0', 'PI'],
-         ['e', 'E'],
-         ['\u03c6', 'GOLDEN_RATIO'],
-         ['sqrt(2)', 'SQRT2'],
-         ['sqrt(\u00bd)', 'SQRT1_2'],
-         ['\u221e', 'INFINITY']];
-    this.setHelpUrl(Blockly.Msg.MATH_CONSTANT_HELPURL);
-    this.setColour(Blockly.Blocks.math.HUE);
-    this.setOutput(true, 'Number');
-    this.appendDummyInput()
-        .appendField(new Blockly.FieldDropdown(CONSTANTS), 'CONSTANT');
-    this.setTooltip(Blockly.Msg.MATH_CONSTANT_TOOLTIP);
+    this.jsonInit({
+      "message0": "%1",
+      "args0": [
+        {
+          "type": "field_dropdown",
+          "name": "CONSTANT",
+          "options": [
+            ['\u03c0', 'PI'],
+            ['e', 'E'],
+            ['\u03c6', 'GOLDEN_RATIO'],
+            ['sqrt(2)', 'SQRT2'],
+            ['sqrt(\u00bd)', 'SQRT1_2'],
+            ['\u221e', 'INFINITY']
+          ]
+        }
+      ],
+      "output": "Number",
+      "colour": Blockly.Blocks.math.HUE,
+      "tooltip": Blockly.Msg.MATH_CONSTANT_TOOLTIP,
+      "helpUrl": Blockly.Msg.MATH_CONSTANT_HELPURL
+    });
   }
 };
 
@@ -297,17 +343,29 @@ Blockly.Blocks['math_round'] = {
    * @this Blockly.Block
    */
   init: function() {
-    var OPERATORS =
-        [[Blockly.Msg.MATH_ROUND_OPERATOR_ROUND, 'ROUND'],
-         [Blockly.Msg.MATH_ROUND_OPERATOR_ROUNDUP, 'ROUNDUP'],
-         [Blockly.Msg.MATH_ROUND_OPERATOR_ROUNDDOWN, 'ROUNDDOWN']];
-    this.setHelpUrl(Blockly.Msg.MATH_ROUND_HELPURL);
-    this.setColour(Blockly.Blocks.math.HUE);
-    this.setOutput(true, 'Number');
-    this.appendValueInput('NUM')
-        .setCheck('Number')
-        .appendField(new Blockly.FieldDropdown(OPERATORS), 'OP');
-    this.setTooltip(Blockly.Msg.MATH_ROUND_TOOLTIP);
+    this.jsonInit({
+      "message0": "%1 %2",
+      "args0": [
+        {
+          "type": "field_dropdown",
+          "name": "OP",
+          "options": [
+            [Blockly.Msg.MATH_ROUND_OPERATOR_ROUND, 'ROUND'],
+            [Blockly.Msg.MATH_ROUND_OPERATOR_ROUNDUP, 'ROUNDUP'],
+            [Blockly.Msg.MATH_ROUND_OPERATOR_ROUNDDOWN, 'ROUNDDOWN']
+          ]
+        },
+        {
+          "type": "input_value",
+          "name": "NUM",
+          "check": "Number"
+        }
+      ],
+      "output": "Number",
+      "colour": Blockly.Blocks.math.HUE,
+      "tooltip": Blockly.Msg.MATH_ROUND_TOOLTIP,
+      "helpUrl": Blockly.Msg.MATH_ROUND_HELPURL
+    });
   }
 };
 
@@ -484,11 +542,12 @@ Blockly.Blocks['math_random_float'] = {
    * @this Blockly.Block
    */
   init: function() {
-    this.setHelpUrl(Blockly.Msg.MATH_RANDOM_FLOAT_HELPURL);
-    this.setColour(Blockly.Blocks.math.HUE);
-    this.setOutput(true, 'Number');
-    this.appendDummyInput()
-        .appendField(Blockly.Msg.MATH_RANDOM_FLOAT_TITLE_RANDOM);
-    this.setTooltip(Blockly.Msg.MATH_RANDOM_FLOAT_TOOLTIP);
+    this.jsonInit({
+      "message0": Blockly.Msg.MATH_RANDOM_FLOAT_TITLE_RANDOM,
+      "output": "Number",
+      "colour": Blockly.Blocks.math.HUE,
+      "tooltip": Blockly.Msg.MATH_RANDOM_FLOAT_TOOLTIP,
+      "helpUrl": Blockly.Msg.MATH_RANDOM_FLOAT_HELPURL
+    });
   }
 };