diff --git a/chapter_02/activity_2.01/main.go b/chapter_02/activity_2.01/main.go
new file mode 100644
index 0000000..f748ef4
--- /dev/null
+++ b/chapter_02/activity_2.01/main.go
@@ -0,0 +1,26 @@
+package main
+
+import (
+  "fmt"
+  "strconv"
+)
+
+func main() {
+
+  var line string
+
+  for i := 1; i <= 100; i++ {
+    if i%3 == 0 {
+      line += "Fizz"
+    }
+    if i%5 == 0 {
+      line += "Buzz"
+    }
+    if len(line) == 0 {
+      line = strconv.Itoa(i)
+    }
+    fmt.Println(line)
+    line = ""
+  }
+
+}
diff --git a/chapter_02/exercise_2.01/main.go b/chapter_02/exercise_2.01/main.go
new file mode 100644
index 0000000..26864d9
--- /dev/null
+++ b/chapter_02/exercise_2.01/main.go
@@ -0,0 +1,16 @@
+package main
+
+import "fmt"
+
+func main() {
+
+  input := 5
+
+  if input%2 == 0 {
+    fmt.Println(input, "is even")
+  }
+  if input%2 == 1 {
+    fmt.Println(input, "is odd")
+  }
+
+}
diff --git a/chapter_02/exercise_2.02/main.go b/chapter_02/exercise_2.02/main.go
new file mode 100644
index 0000000..85343a0
--- /dev/null
+++ b/chapter_02/exercise_2.02/main.go
@@ -0,0 +1,15 @@
+package main
+
+import "fmt"
+
+func main() {
+
+  input := 4
+
+  if input%2 == 0 {
+    fmt.Println(input, "is even")
+  } else {
+    fmt.Println(input, "is odd")
+  }
+
+}
diff --git a/chapter_02/exercise_2.03/main.go b/chapter_02/exercise_2.03/main.go
new file mode 100644
index 0000000..8d42af6
--- /dev/null
+++ b/chapter_02/exercise_2.03/main.go
@@ -0,0 +1,17 @@
+package main
+
+import "fmt"
+
+func main() {
+
+  input := -10
+
+  if input < 0 {
+    fmt.Println("input can't be a negative number")
+  } else if input%2 == 0 {
+    fmt.Println(input, "is even")
+  } else {
+    fmt.Println(input, "is odd")
+  }
+
+}
diff --git a/chapter_02/exercise_2.04/main.go b/chapter_02/exercise_2.04/main.go
new file mode 100644
index 0000000..5578b0b
--- /dev/null
+++ b/chapter_02/exercise_2.04/main.go
@@ -0,0 +1,34 @@
+package main
+
+import (
+  "errors"
+  "fmt"
+)
+
+func validate(input int) error {
+
+  if input < 0 {
+    return errors.New("input can't be a negatice number")
+  } else if input > 100 {
+    return errors.New("input can't be over 100")
+  } else if input%7 == 0 {
+    return errors.New("input can't be divisible by 7")
+  } else {
+    return nil
+  }
+
+}
+
+func main() {
+
+  input := 21
+
+  if err := validate(input); err != nil {
+    fmt.Println(err)
+  } else if input%2 == 0 {
+    fmt.Println(input, "is even")
+  } else {
+    fmt.Println(input, "is odd")
+  }
+
+}