diff --git a/math_probability/power_two/__init__.py b/math_probability/power_two/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/math_probability/power_two/power_two_challenge.ipynb b/math_probability/power_two/power_two_challenge.ipynb
new file mode 100644
index 0000000..4815a68
--- /dev/null
+++ b/math_probability/power_two/power_two_challenge.ipynb
@@ -0,0 +1,171 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Challenge Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Determine if a number is a power of two.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)\n",
+    "* [Solution Notebook](#Solution-Notebook)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Is the input number an int?\n",
+    "    * Yes\n",
+    "* Can we assume the inputs are valid?\n",
+    "    * No\n",
+    "* Is the output a boolean?\n",
+    "    * Yes\n",
+    "* Can we assume this fits memory?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* None -> TypeError\n",
+    "* 0 -> False\n",
+    "* 1 -> True\n",
+    "* 2 -> True\n",
+    "* 15 -> False\n",
+    "* 16 -> True"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the [Solution Notebook]().  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Solution(object):\n",
+    "\n",
+    "    def is_power_of_two(self, val):\n",
+    "        # TODO: Implement me\n",
+    "        pass"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "**The following unit test is expected to fail until you solve the challenge.**"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# %load test_is_power_of_two.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestSolution(object):\n",
+    "\n",
+    "    def test_is_power_of_two(self):\n",
+    "        solution = Solution()\n",
+    "        assert_raises(TypeError, solution.is_power_of_two, None)\n",
+    "        assert_equal(solution.is_power_of_two(0), False)\n",
+    "        assert_equal(solution.is_power_of_two(1), True)\n",
+    "        assert_equal(solution.is_power_of_two(2), True)\n",
+    "        assert_equal(solution.is_power_of_two(15), False)\n",
+    "        assert_equal(solution.is_power_of_two(16), True)\n",
+    "        print('Success: test_is_power_of_two')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestSolution()\n",
+    "    test.test_is_power_of_two()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Solution Notebook\n",
+    "\n",
+    "Review the [Solution Notebook]() for a discussion on algorithms and code solutions."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/math_probability/power_two/power_two_solution.ipynb b/math_probability/power_two/power_two_solution.ipynb
new file mode 100644
index 0000000..9e67bf4
--- /dev/null
+++ b/math_probability/power_two/power_two_solution.ipynb
@@ -0,0 +1,206 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Solution Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Determine if a number is a power of two.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Is the input number an int?\n",
+    "    * Yes\n",
+    "* Can we assume the inputs are valid?\n",
+    "    * No\n",
+    "* Is the output a boolean?\n",
+    "    * Yes\n",
+    "* Can we assume this fits memory?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* None -> TypeError\n",
+    "* 0 -> False\n",
+    "* 1 -> True\n",
+    "* 2 -> True\n",
+    "* 15 -> False\n",
+    "* 16 -> True"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "We can use bit manipulation to determine if a number is a power of two.  \n",
+    "\n",
+    "For a number to be a power of two, there must only be one bit that is a `1`.  \n",
+    "\n",
+    "We can use the following bit manipulation trick to determine this:\n",
+    "\n",
+    "`n & (n - 1)`\n",
+    "\n",
+    "Here's an example why:\n",
+    "\n",
+    "<pre>\n",
+    "0000 1000 = n\n",
+    "0000 0001 = 1\n",
+    "0000 0111 = n-1\n",
+    "\n",
+    "0000 1000 = n\n",
+    "0000 0111 = n-1\n",
+    "0000 0000 = n & n-1, result = 0\n",
+    "</pre>\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(1)\n",
+    "* Space: O(1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Solution(object):\n",
+    "\n",
+    "    def is_power_of_two(self, n):\n",
+    "        if n is None:\n",
+    "            raise TypeError('n cannot be None')\n",
+    "        if n <= 0:\n",
+    "            return False\n",
+    "        return (n & (n - 1)) == 0"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Overwriting test_is_power_of_two.py\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%writefile test_is_power_of_two.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestSolution(object):\n",
+    "\n",
+    "    def test_is_power_of_two(self):\n",
+    "        solution = Solution()\n",
+    "        assert_raises(TypeError, solution.is_power_of_two, None)\n",
+    "        assert_equal(solution.is_power_of_two(0), False)\n",
+    "        assert_equal(solution.is_power_of_two(1), True)\n",
+    "        assert_equal(solution.is_power_of_two(2), True)\n",
+    "        assert_equal(solution.is_power_of_two(15), False)\n",
+    "        assert_equal(solution.is_power_of_two(16), True)\n",
+    "        print('Success: test_is_power_of_two')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestSolution()\n",
+    "    test.test_is_power_of_two()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Success: test_is_power_of_two\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_is_power_of_two.py"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/math_probability/power_two/test_is_power_of_two.py b/math_probability/power_two/test_is_power_of_two.py
new file mode 100644
index 0000000..bdc3ab2
--- /dev/null
+++ b/math_probability/power_two/test_is_power_of_two.py
@@ -0,0 +1,23 @@
+from nose.tools import assert_equal, assert_raises
+
+
+class TestSolution(object):
+
+    def test_is_power_of_two(self):
+        solution = Solution()
+        assert_raises(TypeError, solution.is_power_of_two, None)
+        assert_equal(solution.is_power_of_two(0), False)
+        assert_equal(solution.is_power_of_two(1), True)
+        assert_equal(solution.is_power_of_two(2), True)
+        assert_equal(solution.is_power_of_two(15), False)
+        assert_equal(solution.is_power_of_two(16), True)
+        print('Success: test_is_power_of_two')
+
+
+def main():
+    test = TestSolution()
+    test.test_is_power_of_two()
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file