diff --git a/numberwords.py b/numberwords.py
index 0411373..8d856b0 100644
--- a/numberwords.py
+++ b/numberwords.py
@@ -11,43 +11,47 @@ TWEEN_AND_TEEN_NAMES = [
     "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"
 ]
 TENS_NAMES = [
-    "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
+    "", "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
 ]
 
 def int_under_1000000_to_str(number):
-    "Returns a textual representation of the number."
-    check_number_in_range(abs(number), 0, MAXIMUM)
     if number < 1000:
         return int_under_1000_to_str(number)
     else:
-        thousands, hundreds = divide_with_remainder(number, 1000)
-        thousands_text = int_under_1000_to_str(thousands)
-        hundreds_text = int_under_1000_to_str(hundreds)
-        return thousands_text + " thousand " + hundreds_text
+        thousands, hundreds_tens_ones = divide_with_remainder(number, 1000)
+        if hundreds_tens_ones == 0:
+            return int_under_1000_to_str(thousands) + " thousand"
+        else:
+            return int_under_1000_to_str(thousands) + " thousand " + int_under_1000_to_str(hundreds_tens_ones) 
         
 def int_under_1000_to_str(number):
-    "Returns a textual representation of the number"
-    check_number_in_range(number, 0, 1000)
     if number < 100:
         return int_under_100_to_str(number)
     else:
-        hundreds, tens = divide_with_remainder(number, 100)
-        hundreds_text = int_under_10_to_str(hundreds)
-        tens_text = int_under_100_to_str(tens)
-        return hundreds_text + " hundred and " + tens_text
+        hundreds, tens_and_ones = divide_with_remainder(number, 100)
+        if tens_and_ones == 0:
+            return int_under_10_to_str(hundreds) + " hundred"
+        else:
+            return int_under_10_to_str(hundreds) + " hundred and " + int_under_100_to_str(tens_and_ones)
+
 
 def int_under_100_to_str(number):
-    check_number_in_range(number, 0, 100)
-    tens, ones = divide_with_remainder(number, 10)
-    if tens == 0:
-        return int_under_10_to_str(number)
-    elif tens == 1:
-        return TWEEN_AND_TEEN_NAMES[ones]
+    if number < 20:
+        return int_under_20_to_str(number) 
     else:
-        return TENS_NAMES[tens] + '-' + int_under_10_to_str(ones)
+        tens, ones = divide_with_remainder(number, 10)
+        if ones == 0:
+            return TENS_NAMES[tens]
+        else:
+            return TENS_NAMES[tens] + "-" + int_under_10_to_str(ones)
+
+def int_under_20_to_str(number):
+    if number < 10:
+        return int_under_10_to_str(number)
+    else:
+        return TWEEN_AND_TEEN_NAMES[number-10]    
 
 def int_under_10_to_str(number):
-    check_number_in_range(number, 0, 10)
     return DIGIT_NAMES[number]
 
 def check_number_in_range(number, minimum, maximum):
diff --git a/planning.md b/planning.md
index 40d428a..b80ac19 100644
--- a/planning.md
+++ b/planning.md
@@ -35,21 +35,22 @@ return digit_names[number]
 ```
 
 ## Integers under 20
-If the integer is under 10, then use the procedure described above. 
-Otherwise, ... (this is where you take over!)
+If integer < 10, then return digit_names[number]
+Else return digit_names between 10 and 19
 
 ## Integers under 100
-
+If integer < 20, return "Integers under 20"
+Else return integer between 20 and 99 with proper "and"
 
 ## Integers under 1000
-
+If integer < 100, return "Integers under 100"
+Else return integer between 100 and 999 with proper "and"
 
 ## Integers under 1000000
-
+If integer < 1000, return "Integers under 1000"
+Else return integer between 1000 and 999999 with proper "and"
 
 ## Negative integers down to -1 million
-We won't deal with negative integers in this problem set, 
-but how would you deal with a negative integer, using the 
-functions above?
+Use the above integers but add a negative symbol to all integers and reverse less than to greater than
 
 
diff --git a/test_numberwords.py b/test_numberwords.py
index e40f218..330e638 100644
--- a/test_numberwords.py
+++ b/test_numberwords.py
@@ -12,17 +12,17 @@ test_cases = [
     [11, 'eleven'], 
     [15, 'fifteen'], 
     [18, 'eighteen'], 
-    [43, 'fifty-three'], 
-    [60, 'seventy-zero'], 
-    [89, 'ninety-nine'], 
-    [100, 'one hundred and zero'], 
+    [43, 'forty-three'], 
+    [60, 'sixty'], 
+    [89, 'eighty-nine'], 
+    [100, 'one hundred'], 
     [212, 'two hundred and twelve'], 
-    [755, 'seven hundred and sixty-five'], 
-    [1000, 'one thousand zero'], 
-    [1001, 'one thousand one'], 
+    [755, 'seven hundred and fifty-five'], 
+    [1000, 'one thousand'], 
+    [1001, 'one thousand and one'], 
     [1672, 'one thousand six hundred and eighty-two'], 
-    [10000, 'ten thousand zero'], 
-    [588567, 'five hundred and ninety-eight thousand five hundred and seventy-seven'],
+    [10000, 'ten thousand'], 
+    [588567, 'five hundred and eighty-eight thousand five hundred and sixty-seven'],
 ]
 
 for int_input, expected_output in test_cases: