diff --git a/numberwords.py b/numberwords.py
index 8c590cd..0394a61 100644
--- a/numberwords.py
+++ b/numberwords.py
@@ -15,19 +15,32 @@ TENS_NAMES = [
 ]
 
 def int_under_1000000_to_str(number):
-    return "umm..."
+    return None
         
 def int_under_1000_to_str(number):
-    return "umm..."
+    return None
 
 def int_under_100_to_str(number):
-    return "umm..."
+    if number <20:
+        return int_under_20_to_str
+    elif number <100:
+        prefix = divide_with_remainder(number,10)
+        if number % 10==0:
+           return TENS_NAMES[prefix[0]]
+        else:
+            return (TENS_NAMES[prefix[0]]) + "-" +(DIGIT_NAMES[prefix[1]])
+
 
 def int_under_20_to_str(number):
-    return "umm..."
+    if number <10:
+        return int_under_10_to_str(number)
+    elif number <20:
+        return TWEEN_AND_TEEN_NAMES[number-10]
+    else:
+        return "Error"
 
 def int_under_10_to_str(number):
-    return "umm..."
+    return DIGIT_NAMES[number]
 
 def divide_with_remainder(dividend, divisor):
     """Divides one number by another, using whole-number division. 
diff --git a/nw.py b/nw.py
index 0a0e588..79bac9a 100644
--- a/nw.py
+++ b/nw.py
@@ -4,11 +4,11 @@
 # Ex: python nw.py 145
 
 from argparse import ArgumentParser
-from numberwords import int_under_1000000_to_str
+from numberwords import int_under_100_to_str
 
 parser = ArgumentParser("Print out a number as it is spoken in English.")
 parser.add_argument("number", type=int)
 args = parser.parse_args()
-text = int_under_1000000_to_str(args.number)
+text = int_under_100_to_str(args.number)
 print(text)