diff --git a/go-by-example/functions/functions.go b/go-by-example/functions/functions.go
index ef4e6f1..55cc9c9 100644
--- a/go-by-example/functions/functions.go
+++ b/go-by-example/functions/functions.go
@@ -10,18 +10,51 @@ func plusPlus(a, b, c int) int {
 	return a + b + c
 }
 
+// multiple return values
 func vals() (int, int) {
 	return 3, 7
 }
 
+// variadic functions
+func sum(nums ...int) {
+	fmt.Println(nums, " ")
+	total := 0
+
+	for _, num := range nums {
+		total += num
+	}
+	fmt.Println(total)
+}
+
+// Closures
+func intSeq() func() int {
+	i := 0
+	return func() int {
+		i++
+		return i
+	}
+}
+
+// Recursion
+func fact(n int) int {
+	print(n)
+	print("Recursion")
+	if n == 0 {
+		return 1
+	}
+	return n * fact(n-1)
+}
+
 func main() {
 
+	// functions
 	res := plus(1, 2)
 	fmt.Println("1 + 2 =", res)
 
 	res = plusPlus(1, 2, 3)
 	fmt.Println("1 + 2 + 3 =", res)
 
+	// multiple return values
 	a, b := vals()
 
 	fmt.Println(a)
@@ -30,4 +63,22 @@ func main() {
 	_, c := vals()
 	fmt.Println(c)
 
+	// variadic
+	sum(1, 2, 3, 4, 5, 6)
+	sum(2, 10, 40)
+	sum([]int{5, 10, 10}...)
+
+	// Closures
+	nextInt := intSeq()
+
+	fmt.Println(nextInt())
+	fmt.Println(nextInt())
+	fmt.Println(nextInt())
+
+	newInts := intSeq()
+	fmt.Println(newInts())
+
+	// Recursion
+	// Classic recursion example
+	fmt.Println(fact(7))
 }