diff --git a/hello_cargo/Cargo.lock b/ch1/hello_cargo/Cargo.lock
similarity index 100%
rename from hello_cargo/Cargo.lock
rename to ch1/hello_cargo/Cargo.lock
diff --git a/hello_cargo/Cargo.toml b/ch1/hello_cargo/Cargo.toml
similarity index 100%
rename from hello_cargo/Cargo.toml
rename to ch1/hello_cargo/Cargo.toml
diff --git a/hello_cargo/src/main.rs b/ch1/hello_cargo/src/main.rs
similarity index 100%
rename from hello_cargo/src/main.rs
rename to ch1/hello_cargo/src/main.rs
diff --git a/hello_world/main b/ch1/hello_world/main
similarity index 100%
rename from hello_world/main
rename to ch1/hello_world/main
diff --git a/hello_world/main.rs b/ch1/hello_world/main.rs
similarity index 100%
rename from hello_world/main.rs
rename to ch1/hello_world/main.rs
diff --git a/guessing_game/Cargo.lock b/ch2/guessing_game/Cargo.lock
similarity index 100%
rename from guessing_game/Cargo.lock
rename to ch2/guessing_game/Cargo.lock
diff --git a/guessing_game/Cargo.toml b/ch2/guessing_game/Cargo.toml
similarity index 100%
rename from guessing_game/Cargo.toml
rename to ch2/guessing_game/Cargo.toml
diff --git a/guessing_game/src/main.rs b/ch2/guessing_game/src/main.rs
similarity index 100%
rename from guessing_game/src/main.rs
rename to ch2/guessing_game/src/main.rs
diff --git a/ch3/variables/Cargo.toml b/ch3/variables/Cargo.toml
new file mode 100644
index 0000000..4da3b81
--- /dev/null
+++ b/ch3/variables/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "variables"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/ch3/variables/src/main.rs b/ch3/variables/src/main.rs
new file mode 100644
index 0000000..e7a11a9
--- /dev/null
+++ b/ch3/variables/src/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}