How to use $literal in project to add new field when do a query?

Bids Collection
{ "_id" : 1, "item" : "abc123", price: "2ドル.50" } { "_id" : 2, "item" : "xyz123", price: "1" } { "_id" : 3, "item" : "ijk123", price: "1ドル" }

db.bids.aggregate( [ { $project: { total: { $literal: 100 } } } ] )

{ "_id" : 1, "item" : "abc123", price: "2ドル.50" ,total:100} { "_id" : 2, "item" : "xyz123", price: "1" ,total:100} { "_id" : 3, "item" : "ijk123", price: "1ドル",total:100 }