diff --git a/book/src/4-yul-implementations/4-4-yul-actions/4-4-9-errors.md b/book/src/4-yul-implementations/4-4-yul-actions/4-4-9-errors.md
index 600dd12..b583d8c 100644
--- a/book/src/4-yul-implementations/4-4-yul-actions/4-4-9-errors.md
+++ b/book/src/4-yul-implementations/4-4-yul-actions/4-4-9-errors.md
@@ -31,7 +31,7 @@ pragma solidity ^0.8.0;
 contract Yul {
     // bytes4(keccak256(NumberLess())) => 0x994823ad.
 
-    function revertWithArgs(uint256 num) public pure {
+    function revertWithoutArgs(uint256 num) public pure {
         assembly {
             if lt(num, 0x06) {
                 mstore(0x80, 0x994823ad) // 4 bytes.
@@ -51,7 +51,7 @@ pragma solidity ^0.8.0;
 contract Yul {
     // bytes4(keccak256(NumberLessThan6(uint256))) => 0x8205edea
     
-    function revertWithErrorMessage(uint256 num) public pure {
+    function revertWithArguments(uint256 num) public pure {
         assembly {
             if lt(num, 0x06) {
                 mstore(0x80, 0x8205edea)