How to remove items from an object that do not match when comparing?

There is an object Obj from the property atr whose value is a string. I bring to the number and compare from the variable val , which is a number from 1 to 5.

Example: if val is 5, then remove anything less than or greater than 5 from the object.

It is impossible to remove an element from an object that meets or does not meet the comparison condition.

Tell me how to do this?

 Obj = { atr: "10", atr: "1", atr: "2", atr: "11", atr: "20", atr: "10" }