diff --git a/mathparse/mathparse.py b/mathparse/mathparse.py
index 2db24b3..d09cda9 100644
--- a/mathparse/mathparse.py
+++ b/mathparse/mathparse.py
@@ -3,8 +3,8 @@
 """
 from __future__ import division
 from decimal import Decimal
-import re
 from . import mathwords
+import re
 
 class PostfixTokenEvaluationException(Exception):
     """
@@ -75,6 +75,17 @@ def is_word(word, language):
 
     return word in words
 
+def find_word_groups(string, words):
+    """
+    Find matches for words in the format "3 thousand 6 hundred 2".
+    The words parameter should be the list of words to check for such as "hundred".
+    """
+    scale_pattern = '|'.join(words)
+    # For example: (?:(?:\d+)\s+(?:hundred|thousand|million)*\s*)+(?:\d+|hundred|thousand|million)+
+    regex = re.compile(r'(?:(?:\d+)\s+(?:' + scale_pattern + r')*\s*)+(?:\d+|' + scale_pattern + r')+')
+    result = regex.findall(string)
+    return result
+
 def replace_word_tokens(string, language):
     """
     Given a string and an ISO 639-2 language code,
@@ -86,13 +97,13 @@ def replace_word_tokens(string, language):
     # Replace operator words with numeric operators
     operators = words['binary_operators'].copy()
     operators.update(words['unary_operators'])
-    for operator in operators:
+    for operator in list(operators.keys()):
         if operator in string:
             string = string.replace(operator, operators[operator])
 
     # Replace number words with numeric values
     numbers = words['numbers']
-    for number in numbers:
+    for number in list(numbers.keys()):
         if number in string:
             string = string.replace(number, str(numbers[number]))
 
@@ -100,11 +111,16 @@ def replace_word_tokens(string, language):
     scales = words['scales']
     end_index_characters = mathwords.BINARY_OPERATORS
     end_index_characters.add('(')
-    for scale in scales:
-        for _ in range(string.count(scale)):
-            matches = list(re.finditer(scale, string))
 
-            start_index = matches[0].start() - 1
+    word_matches = find_word_groups(string, list(scales.keys()))
+
+    for match in word_matches:
+        string = string.replace(match, '(' + match + ')')
+
+    for scale in list(scales.keys()):
+        for _ in range(0, string.count(scale)):
+            start_index = string.find(scale) - 1
+            end_index = len(string)
 
             while is_int(string[start_index - 1]) and start_index > 0:
                 start_index -= 1
@@ -112,12 +128,15 @@ def replace_word_tokens(string, language):
             end_index = string.find(' ', start_index) + 1
             end_index = string.find(' ', end_index) + 1
 
-            add = ' +'
+            add = ' + '
             if string[end_index] in end_index_characters:
                 add = ''
 
             string = string[:start_index] + '(' + string[start_index:]
             string = string.replace(scale, '* ' + str(scales[scale]) + ')' + add, 1)
+
+    string = string.replace(') (', ') + (')
+
     return string
 
 
diff --git a/tests/test_binary_operations.py b/tests/test_binary_operations.py
index 149dbb8..d88becd 100644
--- a/tests/test_binary_operations.py
+++ b/tests/test_binary_operations.py
@@ -64,6 +64,11 @@ def test_division_by_zero_words(self):
 
         self.assertEqual(result, 'undefined')
 
+    def test_division_words_large(self):
+        result = mathparse.parse('one thousand two hundred four divided by one hundred', language='ENG')
+
+        self.assertEqual(str(result), '12.04')
+
 
 class PositiveFloatTestCase(TestCase):
 
diff --git a/tests/test_replace_word_tokens.py b/tests/test_replace_word_tokens.py
index d5e93c2..d50c160 100644
--- a/tests/test_replace_word_tokens.py
+++ b/tests/test_replace_word_tokens.py
@@ -17,9 +17,11 @@ def test_thirty(self):
     def test_thousand(self):
         result = mathparse.replace_word_tokens('five thousand + 30', language='ENG')
 
-        self.assertEqual(result, '(5 * 1000) + 30')
+        # Note: this ends up with double parentheses because it is both a
+        # scaled number ("thousand") and a word group ("five thousand")
+        self.assertEqual(result, '((5 * 1000)) + 30')
 
     def test_double_digit_multiplier_for_scale(self):
         result = mathparse.replace_word_tokens('fifty thousand + 1', language='ENG')
 
-        self.assertEqual(result, '(50 * 1000) + 1')
+        self.assertEqual(result, '((50 * 1000)) + 1')