i have task sla related list i'm trying to change list columns but I'm not getting number field

[denny3]

I have a task with a Task SLA related list I'm trying to change list columns but I'm not getting the number and type fields.

[Dr Atul - LNG]

Hi @denny3 

Task field hold the record number. 

[denny3]

How can I get hold of the number field from it?

[Dr Atul - LNG]

 Hi @denny3 

Its already there

[denny3]

I want to add it like this! the picture is from a different table!