diff --git a/All Other Topics/Next in Series.cpp b/All Other Topics/Next in Series.cpp
new file mode 100644
index 0000000..1a63ca1
--- /dev/null
+++ b/All Other Topics/Next in Series.cpp	
@@ -0,0 +1,42 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define MOD 1000000007
+
+int main()
+{
+   int tt;
+   cin>>tt;
+   while(tt--)
+   {
+       int n;
+       cin>>n;
+       long long arr[n];
+       for(int i=0; i<n; i++)
+       {
+           cin>>arr[i];
+       }
+       long long ans=0;
+       if(n==2)
+       {
+           ans=arr[1]+arr[1]-arr[0];
+       }
+       else if((arr[0]+arr[2])==(2*arr[1]))
+       {
+           ans=arr[n-1]+(abs(arr[0]-arr[1]));
+       }
+       else if((arr[0]*arr[2])==powl(arr[1],2) && arr[2]!=0 && arr[0]!=0)
+       {
+           ans=arr[n-1]*(arr[1]/arr[0]);
+       }
+       else if((arr[0]+arr[1])==arr[2])
+       {
+           ans=arr[n-1]+arr[n-2];
+       }
+       else
+       {
+           ans=-99999;
+       }
+       ans=ans%MOD;
+       cout<<ans<<endl;
+   }
+}