Validations for different field in excel

Question

How to validate below item

 

There is column in spreadsheet ParentItem Number(parent) , and Child Item (children) based on that i need to validate data

1. A validation will be displayed if the sum of the parent/children is less than 1.00 for both values for Plan fact column
2. A validation will be displayed if the sum of the effective parent/children is more than 1.00 for Roll Fact column
3. An validation will be displayed if the sum of the Parent Roll-up Factor of the e parent/children is greater than 1.00.

in c #