I have two fields,
1. Start Date  (Date field) eg. 12/10/2020
2. Tenure field (Number field) eg. 2years
I want to create a new field which will calculate the end date based on the two fields above.
i. e End Date field: 12/10/2022

Currently I am using this formula but the output is incorrect. 
"Contract_Start_Date__c + (  Contract_Tenure__c  * 12)"