diff --git a/main.go b/main.go
index 5bdc582..0c4b9b1 100644
--- a/main.go
+++ b/main.go
@@ -32,7 +32,7 @@ func main() {
 	runAndBenchmark("08", "2", false, solutions.Day08Part02)
 
 	runAndBenchmark("09", "1", false, solutions.Day09Part01)
-	runAndBenchmark("09", "2", true, solutions.Day09Part02)
+	runAndBenchmark("09", "2", false, solutions.Day09Part02)
 }
 
 type execute func(bool) int
diff --git a/solutions/day09.go b/solutions/day09.go
index 69877ad..11c5cea 100644
--- a/solutions/day09.go
+++ b/solutions/day09.go
@@ -1,28 +1,14 @@
 package solutions
 
 import (
+	"math"
 	"strconv"
 	"strings"
 )
 
-func Day09Part01(isTest bool) int {
-	input := ReadInput("09", isTest)
-	groups := strings.Split(input, "\n")
-
-	dataSize := len(groups)
-	numbers := make([]int, dataSize)
-
-	for i, str := range groups {
-		value, err := strconv.Atoi(str)
-		if err != nil {
-			panic(err)
-		}
-
-		numbers[i] = value
-	}
-
-	// loop
-	preambleSize := 25
+func findInvalidNumber(preambleSize int, n *[]int) int {
+	numbers := *n
+	dataSize := len(numbers)
 
 out:
 	for i := 0; i < dataSize-preambleSize; i += 1 {
@@ -52,9 +38,89 @@ out:
 	return -1
 }
 
+func Day09Part01(isTest bool) int {
+	input := ReadInput("09", isTest)
+	groups := strings.Split(input, "\n")
+
+	dataSize := len(groups)
+	numbers := make([]int, dataSize)
+
+	for i, str := range groups {
+		value, err := strconv.Atoi(str)
+		if err != nil {
+			panic(err)
+		}
+
+		numbers[i] = value
+	}
+
+	preambleSize := 25
+	if isTest {
+		preambleSize = 5
+	}
+
+	return findInvalidNumber(preambleSize, &numbers)
+}
+
 func Day09Part02(isTest bool) int {
-	// input := ReadInput("09", isTest)
-	// groups := strings.Split(input, "\n")
+	input := ReadInput("09", isTest)
+	groups := strings.Split(input, "\n")
+
+	dataSize := len(groups)
+	numbers := make([]int, dataSize)
+
+	for i, str := range groups {
+		value, err := strconv.Atoi(str)
+		if err != nil {
+			panic(err)
+		}
+
+		numbers[i] = value
+	}
+
+	preambleSize := 25
+	if isTest {
+		preambleSize = 5
+	}
+
+	invalidNumber := findInvalidNumber(preambleSize, &numbers)
+
+	for i := 0; i < len(groups); i += 1 {
+		firstNumber := numbers[i]
+		sum := firstNumber
+
+		resultNumbers := make([]int, 0)
+		resultNumbers = append(resultNumbers, firstNumber)
+
+		for j := i + 1; j < len(groups); j += 1 {
+			currentNumber := numbers[j]
+			sum += currentNumber
+
+			if sum < invalidNumber {
+				resultNumbers = append(resultNumbers, currentNumber)
+			} else if sum == invalidNumber {
+				resultNumbers = append(resultNumbers, currentNumber)
+
+				// Search the smallest & largest numbers in the slice
+
+				smallest := math.MaxInt
+				largest := math.MinInt
+
+				for _, value := range resultNumbers {
+					if value < smallest {
+						smallest = value
+					}
+					if value > largest {
+						largest = value
+					}
+				}
+
+				return smallest + largest
+			} else {
+				break
+			}
+		}
+	}
 
 	return -1
 }