diff --git a/crystal/euler.cr b/crystal/euler.cr
index 2c3f05e..0bf385d 100644
--- a/crystal/euler.cr
+++ b/crystal/euler.cr
@@ -33,47 +33,32 @@ module Euler
     end
   end
 
-  macro prime_factorization_method(given_type)
-    def prime_factorization(n : {{given_type}})
-      result = {} of {{given_type}} => Int32
-      factors = self.trial_division(n)
-
-      factors.each do |f|
-        result[f] = 0
-        num = n
-        while num % f == 0
-          result[f] += 1
-          num /= f
-        end
-      end
-
-      result
-    end
-  end
-
-  macro to_digit_list_method(given_type)
-    def to_digit_list(n : {{given_type}})
-      n.to_s.chars.map { |d| d.to_i }
-    end
-  end
-
-  macro to_big_ints_method(given_type)
-    def to_big_ints(num_list : Array({{given_type}}))
-      num_list.map { |n| BigInt.new(n) }
-    end
-  end
-
   trial_division_method(NumType)
   trial_division_method(BigInt)
 
-  prime_factorization_method(NumType)
-  prime_factorization_method(BigInt)
+  def prime_factorization(n : NumType | BigInt)
+    result = {} of (NumType | BigInt) => Int32
+    factors = self.trial_division(n)
 
-  to_digit_list_method(NumType)
-  to_digit_list_method(BigInt)
+    factors.each do |f|
+      result[f] = 0
+      num = n
+      while num % f == 0
+        result[f] += 1
+        num /= f
+      end
+    end
 
-  to_big_ints_method(NumType)
-  to_big_ints_method(BigInt)
+    result
+  end
+
+  def to_big_ints(num_list : Array(NumType))
+    num_list.map { |n| BigInt.new(n) }
+  end
+
+  def to_digit_list(n : NumType | BigInt)
+    n.to_s.chars.map { |d| d.to_i }
+  end
 
   def palindrome?(x)
     x.to_s.reverse == x.to_s
diff --git a/crystal/euler005.cr b/crystal/euler005.cr
index 18566b8..eebc5e6 100644
--- a/crystal/euler005.cr
+++ b/crystal/euler005.cr
@@ -5,7 +5,7 @@ module Euler
     extend self
 
     def integer_factorization_divisible_by_all_up_to(n)
-      result = {} of Euler::NumType => Euler::NumType
+      result = {} of Euler::NumType | BigInt => Int32
       (2..n).map do |i|
         Euler.prime_factorization(i).each do |prime, exponent|
           if !result.has_key?(prime) || (exponent > result[prime])
@@ -16,7 +16,7 @@ module Euler
       result
     end
 
-    def factors_to_int(factorization : Hash(Euler::NumType, Euler::NumType))
+    def factors_to_int(factorization : Hash(Euler::NumType | BigInt, Int32))
       factorization.map { |prime, exponent| prime ** exponent }.product
     end
 
diff --git a/crystal/prime.cr b/crystal/prime.cr
index 02a5612..99514ad 100644
--- a/crystal/prime.cr
+++ b/crystal/prime.cr
@@ -2,7 +2,6 @@ require "./euler"
 
 module Euler
   class Prime
-    # needs to include BigInt ...
     include Iterator(NumType | BigInt)
 
     def initialize()