diff --git a/src/main/scala/algebra/Monoids.scala b/src/main/scala/algebra/Monoids.scala
index a7d5d5bb431fa76064a218fa6f42bc3719da677c..0f108143837484ce1d4279dd0a1733096f10a7ff 100644
--- a/src/main/scala/algebra/Monoids.scala
+++ b/src/main/scala/algebra/Monoids.scala
@@ -1,15 +1,20 @@
 package algebra
 
-def intAddition: Monoid[Int] = new Monoid[Int] {
+given intAddition: Monoid[Int] with
   def zero = ???
   def combine(a: Int, b: Int): Int = ???
-}
 
-def intMultiplication: Monoid[Int] = ???
+given intMultiplication: Monoid[Int] with
+  def zero = ???
+  def combine(a: Int, b: Int): Int = ???
 
-def booleanOr: Monoid[Boolean] = ???
+given booleanOr: Monoid[Boolean] with
+  def zero = ???
+  def combine(a: Boolean, b: Boolean): Boolean = ???
 
-def booleanAnd: Monoid[Boolean] = ???
+given booleanAnd: Monoid[Boolean] with
+  def zero = ???
+  def combine(a: Boolean, b: Boolean): Boolean = ???
 
 def optionMonoid[A]: Monoid[Option[A]] = ???