diff --git a/advanced_expert/vulnerabilities/arithmetic_errors/README.md b/advanced_expert/vulnerabilities/arithmetic_errors/README.md
index 470bcef..534b547 100644
--- a/advanced_expert/vulnerabilities/arithmetic_errors/README.md
+++ b/advanced_expert/vulnerabilities/arithmetic_errors/README.md
@@ -2,5 +2,7 @@
 
 <br>
 
-* solidity < 0.8: integers in overflow / underflow without any errors.
-* solidity >= 0.8: default behaviour of for overflow / underflow is to throw an error.
+* defaults:
+    * solidity < 0.8: integers in overflow / underflow without any errors.
+    * solidity >= 0.8: default behaviour of for overflow / underflow is to throw an error.
+* use **[SafeMath](https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/SafeMath.sol)** to prevent arithmetic overflow and underflow.