diff --git a/en/16/07.md b/en/16/07.md
index 5aaa7d104b..1af984fa1d 100644
--- a/en/16/07.md
+++ b/en/16/07.md
@@ -24,6 +24,7 @@ material:
             address callerAddress;
             uint256 ethPrice;
           }
+          mapping (uint256=>Response[]) public requestIdToResponse;
           event GetLatestEthPriceEvent(address callerAddress, uint id);
           event SetLatestEthPriceEvent(uint256 ethPrice, address callerAddress);
           event AddOracleEvent(address oracleAddress);
diff --git a/en/16/08.md b/en/16/08.md
index c577332d34..3ab114007c 100644
--- a/en/16/08.md
+++ b/en/16/08.md
@@ -24,6 +24,7 @@ material:
             address callerAddress;
             uint256 ethPrice;
           }
+          mapping (uint256=>Response[]) public requestIdToResponse;
           event GetLatestEthPriceEvent(address callerAddress, uint id);
           event SetLatestEthPriceEvent(uint256 ethPrice, address callerAddress);
           event AddOracleEvent(address oracleAddress);
diff --git a/en/16/09.md b/en/16/09.md
index cd07aa45e3..1daadd3d76 100644
--- a/en/16/09.md
+++ b/en/16/09.md
@@ -26,6 +26,7 @@ material:
             address callerAddress;
             uint256 ethPrice;
           }
+          mapping (uint256=>Response[]) public requestIdToResponse;
           event GetLatestEthPriceEvent(address callerAddress, uint id);
           event SetLatestEthPriceEvent(uint256 ethPrice, address callerAddress);
           event AddOracleEvent(address oracleAddress);
diff --git a/en/16/10.md b/en/16/10.md
index 25ea6daa86..d9360c5cb9 100644
--- a/en/16/10.md
+++ b/en/16/10.md
@@ -26,6 +26,7 @@ material:
             address callerAddress;
             uint256 ethPrice;
           }
+          mapping (uint256=>Response[]) public requestIdToResponse;
           event GetLatestEthPriceEvent(address callerAddress, uint id);
           event SetLatestEthPriceEvent(uint256 ethPrice, address callerAddress);
           event AddOracleEvent(address oracleAddress);
@@ -172,4 +173,4 @@ We're close to being done with the decentralized oracle! Before we conclude, let
 ## Put It to the Test
 
 1. Go ahead and delete the `_id` key from the `requestIdToResponse` map.
-2. Go ahead and update the last two function calls (`callerContractInstance.callback` and `SetLatestEthPriceEvent`), replacing `_ethPrice` with `computedEthPrice`.
\ No newline at end of file
+2. Go ahead and update the last two function calls (`callerContractInstance.callback` and `SetLatestEthPriceEvent`), replacing `_ethPrice` with `computedEthPrice`.