diff --git a/numberwords.py b/numberwords.py
index 8c590cd..1c26418 100644
--- a/numberwords.py
+++ b/numberwords.py
@@ -15,19 +15,47 @@ TENS_NAMES = [
 ]
 
 def int_under_1000000_to_str(number):
-    return "umm..."
+    if 1000 <= number < 1000000:
+       thousands = number // 1000
+       remainder = number % 1000
+       if remainder >0:
+           return int_under_1000_to_str(thousands) + " " + "thousand" + " " + int_under_1000_to_str(remainder)
+       else:
+           return int_under_1000_to_str(thousands)+ " " + "thousand"
+    elif 0 <= number < 1000:
+        return int_under_1000_to_str(number)
         
 def int_under_1000_to_str(number):
-    return "umm..."
+    if 100 <= number < 1000:
+        hundreds = number //100
+        remainder = number % 100
+        if remainder > 0:
+            return DIGIT_NAMES[hundreds]+ " " + "hundred and" + " " + int_under_100_to_str(remainder)
+        else:
+            return DIGIT_NAMES[hundreds]+ " " + "hundred"
+    elif 0<=number<100:
+        return int_under_100_to_str(number)
 
 def int_under_100_to_str(number):
-    return "umm..."
+    if 20 <= number < 100:
+        tens = number // 10
+        ones = number % 10
+        if ones == 0:
+            return TENS_NAMES[tens]
+        else: 
+            return TENS_NAMES[tens] + "-" + DIGIT_NAMES[ones]
+    elif 0<= number <20:
+        return int_under_20_to_str(number)
 
 def int_under_20_to_str(number):
-    return "umm..."
+    if 10 <= number < 20:
+        return TWEEN_AND_TEEN_NAMES[number - 10]
+    elif 0<= number < 10:
+        return int_under_10_to_str(number)
 
 def int_under_10_to_str(number):
-    return "umm..."
+    if 0 <= number < 10:
+        return DIGIT_NAMES[number]
 
 def divide_with_remainder(dividend, divisor):
     """Divides one number by another, using whole-number division. 
diff --git a/test_numberwords.py b/test_numberwords.py
index 0fa6d68..8424af0 100644
--- a/test_numberwords.py
+++ b/test_numberwords.py
@@ -33,7 +33,7 @@ class TestIntToStr(unittest.TestCase):
         [int_under_1000000_to_str, 1001, 'one thousand one'], 
         [int_under_1000000_to_str, 1672, 'one thousand six hundred and seventy-two'], 
         [int_under_1000000_to_str, 10000, 'ten thousand'], 
-        [int_under_1000000_to_str, 588567, 'five hundred and ninety-eight thousand five hundred and sixty-seven'],
+        [int_under_1000000_to_str, 588567, 'five hundred and eighty-eight thousand five hundred and sixty-seven'],
     ]
 
     def test_converts_integer_to_string(self):