diff --git a/common/lib/calc/calc/__init__.py b/common/lib/calc/calc/__init__.py
index e0d80d7b89..d79035ca09 100644
--- a/common/lib/calc/calc/__init__.py
+++ b/common/lib/calc/calc/__init__.py
@@ -3,4 +3,5 @@ Ideally, we wouldn't need to pull in all the calc symbols here,
 but courses were using 'import calc', so we need this for
 backwards compatibility
 """
-from calc import *
+from __future__ import absolute_import
+from .calc import *
diff --git a/common/lib/calc/calc/calc.py b/common/lib/calc/calc/calc.py
index 03af7d9b1c..47066e9c0f 100644
--- a/common/lib/calc/calc/calc.py
+++ b/common/lib/calc/calc/calc.py
@@ -4,6 +4,7 @@ Parser and evaluator for FormulaResponse and NumericalResponse
 Uses pyparsing to parse. Main function as of now is evaluator().
 """
 
+from __future__ import absolute_import
 import math
 import numbers
 import operator
@@ -27,7 +28,9 @@ from pyparsing import (
     stringEnd
 )
 
-import functions
+from . import functions
+import six
+from functools import reduce
 
 # Functions available by default
 # We use scimath variants which give complex results when needed. For example:
@@ -103,7 +106,7 @@ def lower_dict(input_dict):
     variables that have the same lowercase representation. It would be hard to
     tell which is used in the final dict and which isn't.
     """
-    return {k.lower(): v for k, v in input_dict.iteritems()}
+    return {k.lower(): v for k, v in six.iteritems(input_dict)}
 
 
 # The following few functions define evaluation actions, which are run on lists
diff --git a/common/lib/calc/calc/functions.py b/common/lib/calc/calc/functions.py
index d0ac4f7a3d..830e6faa85 100644
--- a/common/lib/calc/calc/functions.py
+++ b/common/lib/calc/calc/functions.py
@@ -4,6 +4,7 @@ Provide the mathematical functions that numpy doesn't.
 Specifically, the secant/cosecant/cotangents and their inverses and
 hyperbolic counterparts
 """
+from __future__ import absolute_import
 import numpy
 
 
diff --git a/common/lib/calc/calc/preview.py b/common/lib/calc/calc/preview.py
index d11d611de9..544776e4ad 100644
--- a/common/lib/calc/calc/preview.py
+++ b/common/lib/calc/calc/preview.py
@@ -8,7 +8,9 @@ Because intermediate values of the render contain more data than simply the
 string of latex, store it in a custom class `LatexRendered`.
 """
 
-from calc import DEFAULT_FUNCTIONS, DEFAULT_VARIABLES, SUFFIXES, ParseAugmenter
+from __future__ import absolute_import
+from .calc import DEFAULT_FUNCTIONS, DEFAULT_VARIABLES, SUFFIXES, ParseAugmenter
+from functools import reduce
 
 
 class LatexRendered(object):
diff --git a/common/lib/calc/calc/tests/test_calc.py b/common/lib/calc/calc/tests/test_calc.py
index befb0afc25..f6ef992b01 100644
--- a/common/lib/calc/calc/tests/test_calc.py
+++ b/common/lib/calc/calc/tests/test_calc.py
@@ -2,10 +2,12 @@
 Unit tests for calc.py
 """
 
+from __future__ import absolute_import
 import unittest
 import numpy
 import calc
 from pyparsing import ParseException
+from six.moves import zip
 
 # numpy's default behavior when it evaluates a function outside its domain
 # is to raise a warning (not an exception) which is then printed to STDOUT.
diff --git a/common/lib/calc/calc/tests/test_preview.py b/common/lib/calc/calc/tests/test_preview.py
index 36d9acbd81..df3913c25f 100644
--- a/common/lib/calc/calc/tests/test_preview.py
+++ b/common/lib/calc/calc/tests/test_preview.py
@@ -3,6 +3,7 @@
 Unit tests for preview.py
 """
 
+from __future__ import absolute_import
 import unittest
 from calc import preview
 import pyparsing
diff --git a/common/lib/calc/setup.py b/common/lib/calc/setup.py
index d62dd9b6eb..453783184e 100644
--- a/common/lib/calc/setup.py
+++ b/common/lib/calc/setup.py
@@ -1,3 +1,4 @@
+from __future__ import absolute_import
 from setuptools import setup
 
 setup(