diff --git a/rustbook/guessing_game/Cargo.lock b/rustbook/guessing_game/Cargo.lock
index 9e771c8..a09bcc1 100644
--- a/rustbook/guessing_game/Cargo.lock
+++ b/rustbook/guessing_game/Cargo.lock
@@ -1,32 +1,24 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "autocfg"
-version = "0.1.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d49d90015b3c36167a20fe2810c5cd875ad504b39cff3d4eae7977e6b7c1cb2"
+version = 3
 
 [[package]]
-name = "bitflags"
-version = "1.2.1"
+name = "cfg-if"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
-name = "cloudabi"
-version = "0.0.3"
+name = "getrandom"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
+checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
 dependencies = [
- "bitflags",
+ "cfg-if",
+ "libc",
+ "wasi",
 ]
 
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-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
-
 [[package]]
 name = "guessing_game"
 version = "0.1.0"
@@ -40,139 +32,54 @@ version = "0.2.80"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4d58d1b70b004888f764dfbf6a26a3b0342a1632d33968e4a179d8011c760614"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac74c624d6b2d21f425f752262f42188365d7b8ff1aff74c82e45136510a4857"
+
 [[package]]
 name = "rand"
-version = "0.6.5"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
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+checksum = "2e7573632e6454cf6b99d7aac4ccca54be06da05aca2ef7423d22d27d4d4bcd8"
 dependencies = [
- "autocfg",
  "libc",
  "rand_chacha",
- "rand_core 0.4.2",
+ "rand_core",
  "rand_hc",
- "rand_isaac",
- "rand_jitter",
- "rand_os",
- "rand_pcg",
- "rand_xorshift",
- "winapi",
 ]
 
 [[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
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- "rand_core 0.3.1",
-]
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-[[package]]
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 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
 dependencies = [
- "rand_core 0.4.2",
+ "ppv-lite86",
+ "rand_core",
 ]
 
 [[package]]
 name = "rand_core"
-version = "0.4.2"
+version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
-
-[[package]]
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-checksum = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
-dependencies = [
- "rand_core 0.3.1",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
 dependencies = [
- "rand_core 0.3.1",
+ "getrandom",
 ]
 
 [[package]]
-name = "rand_jitter"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"
-dependencies = [
- "libc",
- "rand_core 0.4.2",
- "winapi",
-]
-
-[[package]]
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-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
-dependencies = [
- "cloudabi",
- "fuchsia-cprng",
- "libc",
- "rand_core 0.4.2",
- "rdrand",
- "winapi",
-]
-
-[[package]]
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- "autocfg",
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- "rand_core 0.3.1",
-]
-
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-dependencies = [
- "rand_core 0.3.1",
-]
-
-[[package]]
-name = "winapi"
-version = "0.3.9"
+name = "rand_hc"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+checksum = "d51e9f596de227fda2ea6c84607f5558e196eeaf43c986b724ba4fb8fdf497e7"
 dependencies = [
- "winapi-i686-pc-windows-gnu",
- "winapi-x86_64-pc-windows-gnu",
+ "rand_core",
 ]
 
 [[package]]
-name = "winapi-i686-pc-windows-gnu"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
-
-[[package]]
-name = "winapi-x86_64-pc-windows-gnu"
-version = "0.4.0"
+name = "wasi"
+version = "0.10.2+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
diff --git a/rustbook/guessing_game/Cargo.toml b/rustbook/guessing_game/Cargo.toml
index c62139e..dadb87d 100644
--- a/rustbook/guessing_game/Cargo.toml
+++ b/rustbook/guessing_game/Cargo.toml
@@ -7,4 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-rand = "0.6.0"
+rand = "0.8.3"
diff --git a/rustbook/guessing_game/src/main.rs b/rustbook/guessing_game/src/main.rs
index 0d4006e..6064bb5 100644
--- a/rustbook/guessing_game/src/main.rs
+++ b/rustbook/guessing_game/src/main.rs
@@ -5,7 +5,7 @@ use std::io;
 fn main() {
     println!("Guess the number!");
 
-    let secret_number = rand::thread_rng().gen_range(1, 101);
+    let secret_number = rand::thread_rng().gen_range(1..=100);
 
     loop {
         println!("Please input your guess.");