diff --git a/cmds/pxtrequire.ts b/cmds/pxtrequire.ts
deleted file mode 100644
index 0eabce91..00000000
--- a/cmds/pxtrequire.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-/// <reference path="../node_modules/pxt-core/typings/globals/node/index.d.ts"/>
-/// <reference path="../node_modules/pxt-core/built/pxtlib.d.ts" />
-
-import * as path from "path";
-export let pxtCore = require("pxt-core");
-// require.resolve() gives path to [pxt dir]/built/pxt.js, so move up twice to get pxt root dir
-export let pxtCoreDir = path.resolve(require.resolve("pxt-core"), "..", "..");
diff --git a/cmds/tsconfig.json b/cmds/tsconfig.json
deleted file mode 100644
index 7d57cc95..00000000
--- a/cmds/tsconfig.json
+++ /dev/null
@@ -1,13 +0,0 @@
-{
-    "compilerOptions": {
-        "target": "es5",
-        "noImplicitAny": true,
-        "noImplicitReturns": true,
-        "declaration": true,
-        "outDir": "../built",
-        "module": "commonjs",
-        "rootDir": ".",
-        "newLine": "LF",
-        "sourceMap": false
-    }
-}
diff --git a/libs/core/_locales/core-jsdoc-strings.json b/libs/core/_locales/core-jsdoc-strings.json
index 3b40fcb0..7af391d7 100644
--- a/libs/core/_locales/core-jsdoc-strings.json
+++ b/libs/core/_locales/core-jsdoc-strings.json
@@ -102,6 +102,16 @@
   "Math": "More complex operations with numbers.",
   "Math.abs": "Returns the absolute value of a number (the value without regard to whether it is positive or negative).\nFor example, the absolute value of -5 is the same as the absolute value of 5.",
   "Math.abs|param|x": "A numeric expression for which the absolute value is needed.",
+  "Math.ceil": "Returns the smallest number greater than or equal to its numeric argument.",
+  "Math.ceil|param|x": "A numeric expression.",
+  "Math.floor": "Returns the greatest number less than or equal to its numeric argument.",
+  "Math.floor|param|x": "A numeric expression.",
+  "Math.idiv": "Returns the value of integer signed 32 bit division of two numbers.",
+  "Math.idiv|param|x": "The first number",
+  "Math.idiv|param|y": "The second number",
+  "Math.imul": "Returns the value of integer signed 32 bit multiplication of two numbers.",
+  "Math.imul|param|x": "The first number",
+  "Math.imul|param|y": "The second number",
   "Math.max": "Returns the larger of two supplied numeric expressions.",
   "Math.min": "Returns the smaller of two supplied numeric expressions.",
   "Math.pow": "Return the value of a base expression taken to a specified power.",
@@ -110,10 +120,14 @@
   "Math.random": "Return a pseudorandom number between 0 and `limit`.",
   "Math.randomBoolean": "Generates a `true` or `false` value randomly, just like flipping a coin.",
   "Math.random|param|limit": "the upper bound of the number generated, eg: 4",
+  "Math.round": "Returns a supplied numeric expression rounded to the nearest number.",
+  "Math.round|param|x": "The value to be rounded to the nearest number.",
   "Math.sign": "Returns the sign of the x, indicating whether x is positive, negative or zero.",
   "Math.sign|param|x": "The numeric expression to test",
   "Math.sqrt": "Return the square root of a number.",
   "Math.sqrt|param|x": "A numeric expression.",
+  "Math.trunc": "Returns the number with the decimal part truncated.",
+  "Math.trunc|param|x": "A numeric expression.",
   "Number.toString": "Return a string representation of a number.",
   "String": "Combine, split, and search text strings.\n\nCombine, split, and search text strings.",
   "String.charAt": "Return the character at the specified index.",
@@ -371,7 +385,7 @@
   "music.speakerPlayTone|param|frequency": "pitch of the tone to play in Hertz (Hz)",
   "music.speakerPlayTone|param|ms": "tone duration in milliseconds (ms)",
   "music.tempo": "Returns the tempo in beats per minute. Tempo is the speed (bpm = beats per minute) at which notes play. The larger the tempo value, the faster the notes will play.",
-  "parseInt": "Convert A string to an integer.",
+  "parseInt": "Convert a string to an integer.",
   "pins": "Control currents in Pins for analog/digital signals, servos, i2c, ...",
   "pins.analogPitch": "Emits a Pulse-width modulation (PWM) signal to the current pitch pin. Use `analog set pitch pin` to define the pitch pin.",
   "pins.analogPitch|param|frequency": "frequency to modulate in Hz.",
diff --git a/package.json b/package.json
index fefe401d..b115342c 100644
--- a/package.json
+++ b/package.json
@@ -26,8 +26,6 @@
     "docs/*/*.md",
     "docs/*/*/*.md"
   ],
-  "main": "built/pxtrequire.js",
-  "typings": "built/pxtrequire.d.ts",
   "devDependencies": {
     "typescript": "^1.8.7",
     "rtlcss": "^2.1.2",
@@ -36,7 +34,7 @@
     "semantic-ui-less": "2.2.14"
   },
   "dependencies": {
-    "pxt-core": "0.18.5"
+    "pxt-core": "0.19.7"
   },
   "scripts": {
     "test": "node node_modules/pxt-core/built/pxt.js travis"